Нашёл проблему. Нужно запускать steam-native. Похоже, что библиотеки runtime стали некорректно работать с Линукс.
Тему можно закрыть.
lychenkoff
Мне помогли такие действия: меню Steam - Настройки - Steam Play - Выбрать Proton 5 (по умолчанию стоял какой-то Soldier)
У меня никогда не стоял Soldier. Всегда установлен именно Proton
Вы пробовали менять сервера загрузки в настройках Steam?

Да пробовал. Бесполезно.
И кэш загрузки я тоже чистил. Он, собственно говоря, итак пустой, ибо я не смог начать загрузку. На Виндовс такой проблемы не замечено.
видно, что игра запускается через протон, скорее всего, но понять что за игра не представляется возможным.
есть сайт по данному вопросу - protondb.com, в котором публикуют разного рода отзывы о возможных способах запуска игры.

Вы точно в нужной теме это пишете? Прочтите ещё раз какая у меня проблема :)
Помогите! Steam долгое время не может начать загрузку. Спустя время загрузка начинается, но позже загрузка падает до нуля.

Running Steam on arch rolling 64-bit
STEAM_RUNTIME is enabled automatically
Pins up-to-date!
Steam client's requirements are satisfied
/home/stanislav/.local/share/Steam/ubuntu12_32/steam
[2020-09-07 19:59:28] Startup - updater built Sep  3 2020 21:18:09
Installing breakpad exception handler for appid(steam)/version(1599174997)
Looks like steam didn't shutdown cleanly, scheduling immediate update check
Installing breakpad exception handler for appid(steam)/version(1599174997)
[2020-09-07 19:59:28] Checking for update on startup
[2020-09-07 19:59:28] Проверка на наличие обновлений...
[2020-09-07 19:59:28] Downloading manifest: client-download.steampowered.com/client/steam_client_ubuntu12
Installing breakpad exception handler for appid(steam)/version(1599174997)
[2020-09-07 19:59:30] Download skipped: /client/steam_client_ubuntu12 version 1599174997, installed version 1599174997, downloaded version 0
[2020-09-07 19:59:30] Nothing to do
[2020-09-07 19:59:30] Проверка установки...
[2020-09-07 19:59:30] Performing checksum verification of executable files
[2020-09-07 19:59:40] Verification complete
Loaded SDL version 2.0.13-5919606

(steam:1916): Gtk-WARNING **: 19:59:40.385: Unable to locate theme engine in module_path: "murrine",

(steam:1916): Gtk-WARNING **: 19:59:40.386: Unable to locate theme engine in module_path: "murrine",

(steam:1916): Gtk-WARNING **: 19:59:40.386: Unable to locate theme engine in module_path: "murrine",

(steam:1916): Gtk-WARNING **: 19:59:40.386: Unable to locate theme engine in module_path: "murrine",

(steam:1916): Gtk-WARNING **: 19:59:40.386: Unable to locate theme engine in module_path: "murrine",

(steam:1916): Gtk-WARNING **: 19:59:40.386: Unable to locate theme engine in module_path: "murrine",

(steam:1916): Gtk-WARNING **: 19:59:40.386: Unable to locate theme engine in module_path: "murrine",

(steam:1916): Gtk-WARNING **: 19:59:40.387: Unable to locate theme engine in module_path: "murrine",

(steam:1916): Gtk-WARNING **: 19:59:40.387: Unable to locate theme engine in module_path: "murrine",

(steam:1916): Gtk-WARNING **: 19:59:40.387: Unable to locate theme engine in module_path: "murrine",

(steam:1916): Gtk-WARNING **: 19:59:40.387: Unable to locate theme engine in module_path: "murrine",

(steam:1916): Gtk-WARNING **: 19:59:40.387: Unable to locate theme engine in module_path: "murrine",

(steam:1916): Gtk-WARNING **: 19:59:40.387: Unable to locate theme engine in module_path: "murrine",

(steam:1916): Gtk-WARNING **: 19:59:40.387: Unable to locate theme engine in module_path: "murrine",

(steam:1916): Gtk-WARNING **: 19:59:40.387: Unable to locate theme engine in module_path: "murrine",

(steam:1916): Gtk-WARNING **: 19:59:40.387: Unable to locate theme engine in module_path: "murrine",

(steam:1916): Gtk-WARNING **: 19:59:40.387: Unable to locate theme engine in module_path: "murrine",

(steam:1916): Gtk-WARNING **: 19:59:40.387: Unable to locate theme engine in module_path: "murrine",

(steam:1916): Gtk-WARNING **: 19:59:40.387: Unable to locate theme engine in module_path: "murrine",

(steam:1916): Gtk-WARNING **: 19:59:40.387: Unable to locate theme engine in module_path: "murrine",

(steam:1916): Gtk-WARNING **: 19:59:40.387: Unable to locate theme engine in module_path: "murrine",

(steam:1916): Gtk-WARNING **: 19:59:40.387: Unable to locate theme engine in module_path: "murrine",

(steam:1916): Gtk-WARNING **: 19:59:40.387: Unable to locate theme engine in module_path: "murrine",

(steam:1916): Gtk-WARNING **: 19:59:40.387: Unable to locate theme engine in module_path: "murrine",

(steam:1916): Gtk-WARNING **: 19:59:40.388: Unable to locate theme engine in module_path: "murrine",

(steam:1916): Gtk-WARNING **: 19:59:40.388: Unable to locate theme engine in module_path: "murrine",

(steam:1916): Gtk-WARNING **: 19:59:40.388: Unable to locate theme engine in module_path: "murrine",

(steam:1916): Gtk-WARNING **: 19:59:40.388: Unable to locate theme engine in module_path: "murrine",

(steam:1916): Gtk-WARNING **: 19:59:40.388: Unable to locate theme engine in module_path: "murrine",

(steam:1916): Gtk-WARNING **: 19:59:40.388: Unable to locate theme engine in module_path: "murrine",

(steam:1916): Gtk-WARNING **: 19:59:40.389: Unable to locate theme engine in module_path: "murrine",

(steam:1916): Gtk-WARNING **: 19:59:40.390: Unable to locate theme engine in module_path: "murrine",

(steam:1916): Gtk-WARNING **: 19:59:40.390: Unable to locate theme engine in module_path: "murrine",
STEAM_RUNTIME_HEAVY: ./steam-runtime-heavy
Installing breakpad exception handler for appid(steam)/version(1599174997)
[0907/195940.993583:INFO:crash_reporting.cc(247)] Crash reporting enabled for process: browser
[0907/195941.336507:WARNING:crash_reporting.cc(286)] Failed to set crash key: UserID with value: 0
[0907/195941.336545:WARNING:crash_reporting.cc(286)] Failed to set crash key: BuildID with value: 1599167902
[0907/195941.336550:WARNING:crash_reporting.cc(286)] Failed to set crash key: SteamUniverse with value: Public
[0907/195941.336553:WARNING:crash_reporting.cc(286)] Failed to set crash key: Vendor with value: Valve
[0907/195941.381681:WARNING:crash_reporting.cc(286)] Failed to set crash key: UserID with value: 0
[0907/195941.381722:WARNING:crash_reporting.cc(286)] Failed to set crash key: BuildID with value: 1599167902
[0907/195941.381726:WARNING:crash_reporting.cc(286)] Failed to set crash key: SteamUniverse with value: Public
[0907/195941.381730:WARNING:crash_reporting.cc(286)] Failed to set crash key: Vendor with value: Valve
[0907/195941.382279:INFO:crash_reporting.cc(247)] Crash reporting enabled for process: gpu-process
[0907/195941.448956:ERROR:sandbox_linux.cc(372)] InitializeSandbox() called with multiple threads in process gpu-process.
Installing breakpad exception handler for appid(steam)/version(1599174997)
Installing breakpad exception handler for appid(steam)/version(1599174997)
Installing breakpad exception handler for appid(steam)/version(1599174997)
[0907/195941.508529:WARNING:crash_reporting.cc(286)] Failed to set crash key: UserID with value: 0
[0907/195941.508567:WARNING:crash_reporting.cc(286)] Failed to set crash key: BuildID with value: 1599167902
[0907/195941.508573:WARNING:crash_reporting.cc(286)] Failed to set crash key: SteamUniverse with value: Public
[0907/195941.508576:WARNING:crash_reporting.cc(286)] Failed to set crash key: Vendor with value: Valve
[0907/195941.509267:INFO:crash_reporting.cc(247)] Crash reporting enabled for process: utility
CAppInfoCacheReadFromDiskThread took 204 milliseconds to initialize
Installing breakpad exception handler for appid(steam)/version(1599174997)
Installing breakpad exception handler for appid(steam)/version(1599174997)
Installing breakpad exception handler for appid(steam)/version(1599174997)
Installing breakpad exception handler for appid(steam)/version(1599174997)
Installing breakpad exception handler for appid(steam)/version(1599174997)
Installing breakpad exception handler for appid(steam)/version(1599174997)
Installing breakpad exception handler for appid(steam)/version(1599174997)
Warning: failed to set thread priority: set failed for 8: -1: setpriority() failed
Warning: failed to set thread priority: set failed for priority 8
Warning: support for elevated priorities is most likely unavailable, suppressing future warnings
Warning: failed to set thread priority: set failed for 8: -1: setpriority() failed
CApplicationManagerPopulateThread took 1347 milliseconds to initialize (will have waited on CAppInfoCacheReadFromDiskThread)
Installing breakpad exception handler for appid(steam)/version(1599174997)
Installing breakpad exception handler for appid(steam)/version(1599174997)
Installing breakpad exception handler for appid(steam)/version(1599174997)
Proceed to auto login
Opted-in Controller Mask for AppId 0: 0
Installing breakpad exception handler for appid(steam)/version(1599174997)
Installing breakpad exception handler for appid(steam)/version(1599174997)
Installing breakpad exception handler for appid(steam)/version(1599174997)
Installing breakpad exception handler for appid(steam)/version(1599174997)

(steam:1916): Gtk-WARNING **: 19:59:43.968: gtk_disable_setlocale() must be called before gtk_init()
Installing breakpad exception handler for appid(steam)/version(1599174997)
Installing breakpad exception handler for appid(steam)/version(1599174997)
local (potentially out of sync) copy of roaming config loaded - 746 bytes.
Installing breakpad exception handler for appid(steam)/version(1599174997)
roaming config store loaded successfully - 746 bytes.
migrating temporary roaming config store
BRefreshApplicationsInLibrary 1: 8ms
[0907/195954.301316:INFO:crash_reporting.cc(270)] Crash reporting enabled for process: renderer
[0907/195954.825048:INFO:crash_reporting.cc(270)] Crash reporting enabled for process: renderer
[0907/195954.960605:INFO:crash_reporting.cc(270)] Crash reporting enabled for process: renderer
Installing breakpad exception handler for appid(steam)/version(1599174997)
Failed to init SteamVR because it isn't installed
ExecCommandLine: "'/home/stanislav/.local/share/Steam/ubuntu12_32/steam'"
System startup time: 16.13 seconds
[0907/195956.373422:INFO:crash_reporting.cc(270)] Crash reporting enabled for process: renderer
Warning: failed to set thread priority: set failed for 4: -1: setpriority() failed
Warning: failed to set thread priority: set failed for priority 4
Warning: support for elevated priorities is most likely unavailable, suppressing future warnings
[0907/195956.375031:INFO:crash_reporting.cc(270)] Crash reporting enabled for process: renderer
[0907/195956.378253:INFO:crash_reporting.cc(270)] Crash reporting enabled for process: renderer
Warning: failed to set thread priority: set failed for 4: -1: setpriority() failed
Warning: failed to set thread priority: set failed for priority 4
Warning: support for elevated priorities is most likely unavailable, suppressing future warnings
BuildCompleteAppOverviewChange: 509
RegisterForAppOverview 1: 13ms
RegisterForAppOverview 2: 13ms
Installing breakpad exception handler for appid(steam)/version(1599174997)
Installing breakpad exception handler for appid(steam)/version(1599174997)
[0907/195959.852125:ERROR:object_proxy.cc(632)] Failed to call method: org.freedesktop.ScreenSaver.Inhibit: object_path= /org/freedesktop/ScreenSaver: org.freedesktop.DBus.Error.ServiceUnknown: The name org.freedesktop.ScreenSaver was not provided by any .service files
[0907/195959.852160:ERROR:power_save_blocker_x11.cc(330)] No response to Inhibit() request!
Installing breakpad exception handler for appid(steam)/version(1599174997)
Installing breakpad exception handler for appid(steam)/version(1599174997)
ExecuteSteamURL: "steam://open/downloads"
[0907/200029.584682:ERROR:object_proxy.cc(632)] Failed to call method: org.freedesktop.ScreenSaver.UnInhibit: object_path= /org/freedesktop/ScreenSaver: org.freedesktop.DBus.Error.ServiceUnknown: The name org.freedesktop.ScreenSaver was not provided by any .service files
[0907/200029.584732:ERROR:power_save_blocker_x11.cc(403)] No response to Uninhibit() request!
ExecuteSteamURL: "steam://nav/library/details/1245040"
[1245040]Non-Steam Controller Configs Enabled: 1
Installing breakpad exception handler for appid(steam)/version(1599174997)
CAPIJobRequestUserStats - Server response failed 2
ExecuteSteamURL: "steam://open/downloads"
Installing breakpad exception handler for appid(steam)/version(1599174997)
Installing breakpad exception handler for appid(steam)/version(1599174997)
Installing breakpad exception handler for appid(steam)/version(1599174997)
Installing breakpad exception handler for appid(steam)/version(1599174997)
Installing breakpad exception handler for appid(steam)/version(1599174997)
Installing breakpad exception handler for appid(steam)/version(1599174997)
Installing breakpad exception handler for appid(steam)/version(1599174997)
Installing breakpad exception handler for appid(steam)/version(1599174997)
ExecuteSteamURL: "steam://nav/library/details/1245040"
ExecuteSteamURL: "steam://open/downloads"
[2020-09-07 20:04:11] Background update loop checking for update. . .
[2020-09-07 20:04:11] Проверка на наличие обновлений...
[2020-09-07 20:04:11] Downloading manifest: client-download.steampowered.com/client/steam_client_ubuntu12
[2020-09-07 20:04:11] Download skipped by HTTP 304 Not Modified
[2020-09-07 20:04:11] Nothing to do
ExecuteSteamURL: "steam://nav/library/details/1245040"
ExecuteSteamURL: "steam://open/downloads"
Как и многим другим, а сервера может на всех и не хватать. Потому удаленный может отдавать быстрее чем московский.
https://store.steampowered.com/stats/content/
Нет. Не помогает
Я живу в центре. Мне Москва подходит лучше всего :)
Сменить попробуйте,сервер может быть перегружен
Пробовал USA - New York. Всё так же. Возможно после последних обновлений networkmanager такая проблема начала появляться. Раньше всё работало "из коробки"
Регион стоит по умолчанию. Russia - Moscow
После добавления в загрузку, минут 5-10 не качает. Потом начинает скачивать:

[stanislav@pc ~]$ steam
Running Steam on arch rolling 64-bit
STEAM_RUNTIME is enabled automatically
Pins up-to-date!
/home/stanislav/.local/share/Steam/ubuntu12_32/steam
Installing breakpad exception handler for appid(steam)/version(1581460722)
Installing breakpad exception handler for appid(steam)/version(1581460722)
Installing breakpad exception handler for appid(steam)/version(1581460722)
Installing breakpad exception handler for appid(steam)/version(1581460722)
STEAM_RUNTIME_HEAVY: ./steam-runtime-heavy
[0313/165655.666275:INFO:crash_reporting.cc(247)] Crash reporting enabled for process: browser
[0313/165655.687629:WARNING:crash_reporting.cc(286)] Failed to set crash key: UserID with value: 0
[0313/165655.687701:WARNING:crash_reporting.cc(286)] Failed to set crash key: BuildID with value: 1581449474
[0313/165655.687706:WARNING:crash_reporting.cc(286)] Failed to set crash key: SteamUniverse with value: Public
[0313/165655.687709:WARNING:crash_reporting.cc(286)] Failed to set crash key: Vendor with value: Valve
[0313/165655.745794:WARNING:crash_reporting.cc(286)] Failed to set crash key: UserID with value: 0
[0313/165655.745855:WARNING:crash_reporting.cc(286)] Failed to set crash key: BuildID with value: 1581449474
[0313/165655.745861:WARNING:crash_reporting.cc(286)] Failed to set crash key: SteamUniverse with value: Public
[0313/165655.745864:WARNING:crash_reporting.cc(286)] Failed to set crash key: Vendor with value: Valve
[0313/165655.746325:INFO:crash_reporting.cc(247)] Crash reporting enabled for process: gpu-process
Installing breakpad exception handler for appid(steam)/version(1581460722)
Installing breakpad exception handler for appid(steam)/version(1581460722)
Installing breakpad exception handler for appid(steam)/version(1581460722)
Installing breakpad exception handler for appid(steam)/version(1581460722)
Installing breakpad exception handler for appid(steam)/version(1581460722)
Installing breakpad exception handler for appid(steam)/version(1581460722)
CApplicationManagerPopulateThread took 12 milliseconds to initialize (will have waited on CAppInfoCacheReadFromDiskThread)
[0313/165656.030800:WARNING:crash_reporting.cc(286)] Failed to set crash key: UserID with value: 0
[0313/165656.030876:WARNING:crash_reporting.cc(286)] Failed to set crash key: BuildID with value: 1581449474
[0313/165656.030883:WARNING:crash_reporting.cc(286)] Failed to set crash key: SteamUniverse with value: Public
[0313/165656.030889:WARNING:crash_reporting.cc(286)] Failed to set crash key: Vendor with value: Valve
[0313/165656.031520:INFO:crash_reporting.cc(247)] Crash reporting enabled for process: utility
Installing breakpad exception handler for appid(steam)/version(1581460722)
Installing breakpad exception handler for appid(steam)/version(1581460722)
Installing breakpad exception handler for appid(steam)/version(1581460722)
Installing breakpad exception handler for appid(steam)/version(1581460722)
Installing breakpad exception handler for appid(steam)/version(1581460722)
Installing breakpad exception handler for appid(steam)/version(1581460722)
Installing breakpad exception handler for appid(steam)/version(1581460722)
Installing breakpad exception handler for appid(steam)/version(1581460722)
Installing breakpad exception handler for appid(steam)/version(1581460722)
Installing breakpad exception handler for appid(steam)/version(1581460722)
CAppInfoCacheReadFromDiskThread took 150 milliseconds to initialize
Installing breakpad exception handler for appid(steam)/version(1581460722)
Installing breakpad exception handler for appid(steam)/version(1581460722)
Installing breakpad exception handler for appid(steam)/version(1581460722)
Opted-in Controller Mask for AppId 0: 0
Installing breakpad exception handler for appid(steam)/version(1581460722)

(steam:5587): Gtk-WARNING **: 16:56:56.901: gtk_disable_setlocale() must be called before gtk_init()

(steam:5587): LIBDBUSMENU-GLIB-WARNING **: 16:56:56.957: Trying to remove a child that doesn't believe we're it's parent.

(steam:5587): LIBDBUSMENU-GLIB-WARNING **: 16:56:56.957: Trying to remove a child that doesn't believe we're it's parent.

(steam:5587): LIBDBUSMENU-GLIB-WARNING **: 16:56:56.957: Trying to remove a child that doesn't believe we're it's parent.

(steam:5587): LIBDBUSMENU-GLIB-WARNING **: 16:56:56.957: Trying to remove a child that doesn't believe we're it's parent.

(steam:5587): LIBDBUSMENU-GLIB-WARNING **: 16:56:56.957: Trying to remove a child that doesn't believe we're it's parent.

(steam:5587): LIBDBUSMENU-GLIB-WARNING **: 16:56:56.957: Trying to remove a child that doesn't believe we're it's parent.

(steam:5587): LIBDBUSMENU-GLIB-WARNING **: 16:56:56.957: Trying to remove a child that doesn't believe we're it's parent.

(steam:5587): LIBDBUSMENU-GLIB-WARNING **: 16:56:56.958: Trying to remove a child that doesn't believe we're it's parent.

(steam:5587): LIBDBUSMENU-GLIB-WARNING **: 16:56:56.958: Trying to remove a child that doesn't believe we're it's parent.
Fossilize INFO: Overriding serialization path: "/home/stanislav/.local/share/Steam/shader_cache_temp_dir_vk_64/fozpipelinesv4/steamapprun_pipeline_cache".
roaming config store loaded successfully - 7489 bytes.
migrating temporary roaming config store
BRefreshApplicationsInLibrary 1: 28ms
[0313/165700.206963:INFO:crash_reporting.cc(270)] Crash reporting enabled for process: renderer
[0313/165700.283291:INFO:crash_reporting.cc(270)] Crash reporting enabled for process: renderer
[0313/165700.376580:INFO:crash_reporting.cc(270)] Crash reporting enabled for process: renderer
Installing breakpad exception handler for appid(steam)/version(1581460722)
Failed to init SteamVR because it isn't installed
ExecCommandLine: "'/home/stanislav/.local/share/Steam/ubuntu12_32/steam'"
System startup time: 6.27 seconds

(steam:5587): LIBDBUSMENU-GLIB-WARNING **: 16:57:01.208: Trying to remove a child that doesn't believe we're it's parent.

(steam:5587): LIBDBUSMENU-GLIB-WARNING **: 16:57:01.208: Trying to remove a child that doesn't believe we're it's parent.

(steam:5587): LIBDBUSMENU-GLIB-WARNING **: 16:57:01.209: Trying to remove a child that doesn't believe we're it's parent.

(steam:5587): LIBDBUSMENU-GLIB-WARNING **: 16:57:01.209: Trying to remove a child that doesn't believe we're it's parent.

(steam:5587): LIBDBUSMENU-GLIB-WARNING **: 16:57:01.209: Trying to remove a child that doesn't believe we're it's parent.

(steam:5587): LIBDBUSMENU-GLIB-WARNING **: 16:57:01.209: Trying to remove a child that doesn't believe we're it's parent.

(steam:5587): LIBDBUSMENU-GLIB-WARNING **: 16:57:01.209: Trying to remove a child that doesn't believe we're it's parent.

(steam:5587): LIBDBUSMENU-GLIB-WARNING **: 16:57:01.209: Trying to remove a child that doesn't believe we're it's parent.

(steam:5587): LIBDBUSMENU-GLIB-WARNING **: 16:57:01.210: Trying to remove a child that doesn't believe we're it's parent.

(steam:5587): LIBDBUSMENU-GLIB-WARNING **: 16:57:01.210: Trying to remove a child that doesn't believe we're it's parent.

(steam:5587): LIBDBUSMENU-GLIB-WARNING **: 16:57:01.210: Trying to remove a child that doesn't believe we're it's parent.

(steam:5587): LIBDBUSMENU-GLIB-WARNING **: 16:57:01.210: Trying to remove a child that doesn't believe we're it's parent.

(steam:5587): LIBDBUSMENU-GLIB-WARNING **: 16:57:01.210: Trying to remove a child that doesn't believe we're it's parent.

(steam:5587): LIBDBUSMENU-GLIB-WARNING **: 16:57:01.211: Trying to remove a child that doesn't believe we're it's parent.

(steam:5587): LIBDBUSMENU-GLIB-WARNING **: 16:57:01.211: Trying to remove a child that doesn't believe we're it's parent.
[0313/165701.224270:INFO:crash_reporting.cc(270)] Crash reporting enabled for process: renderer
[0313/165701.229427:INFO:crash_reporting.cc(270)] Crash reporting enabled for process: renderer
[0313/165701.234221:INFO:crash_reporting.cc(270)] Crash reporting enabled for process: renderer
BuildCompleteAppOverviewChange: 472
RegisterForAppOverview 1: 32ms
RegisterForAppOverview 2: 33ms
ExecuteSteamURL: "steam://open/downloads"
[0313/165704.922683:ERROR:frame_sink_video_capturer_impl.cc(197)] Invalid resolutions constraints: 0x0 must not be greater than 0x0; and also within media::limits.
Installing breakpad exception handler for appid(steam)/version(1581460722)
Installing breakpad exception handler for appid(steam)/version(1581460722)