But, anyway, I've try to set up Steam from Flatpak... But there's absolutely the same result:
chdir "/mnt/Games/Steam/steamapps/common/Super Blue Boy Planet"
Game Recording - would start recording game 560260, but recording for this game is disabled
Adding process 1300 for gameID 560260
ERROR: ld.so: object '/home/user/.var/app/com.valvesoftware.Steam/.local/share/Steam/ubuntu12_32/gameoverlayrenderer.so' from LD_PRELOAD cannot be preloaded (wrong ELF class: ELFCLASS32): ignored.
ERROR: ld.so: object '/home/user/.var/app/com.valvesoftware.Steam/.local/share/Steam/ubuntu12_32/gameoverlayrenderer.so' from LD_PRELOAD cannot be preloaded (wrong ELF class: ELFCLASS32): ignored.
ERROR: ld.so: object '/home/user/.var/app/com.valvesoftware.Steam/.local/share/Steam/ubuntu12_64/gameoverlayrenderer.so' from LD_PRELOAD cannot be preloaded (wrong ELF class: ELFCLASS64): ignored.
ERROR: ld.so: object '/home/user/.var/app/com.valvesoftware.Steam/.local/share/Steam/ubuntu12_32/gameoverlayrenderer.so' from LD_PRELOAD cannot be preloaded (wrong ELF class: ELFCLASS32): ignored.
ERROR: ld.so: object '/home/user/.var/app/com.valvesoftware.Steam/.local/share/Steam/ubuntu12_32/gameoverlayrenderer.so' from LD_PRELOAD cannot be preloaded (wrong ELF class: ELFCLASS32): ignored.
WARNING: discarding _NET_WM_PID 2416 as invalid for X11 window - use specialized XCB_X11_TO_PID function!
WARNING: discarding _NET_WM_PID 2419 as invalid for X11 window - use specialized XCB_X11_TO_PID function!
WARNING: discarding _NET_WM_PID 2731 as invalid for X11 window - use specialized XCB_X11_TO_PID function!
WARNING: discarding _NET_WM_PID 3245 as invalid for X11 window - use specialized XCB_X11_TO_PID function!
WARNING: discarding _NET_WM_PID 12018 as invalid for X11 window - use specialized XCB_X11_TO_PID function!
Adding process 1301 for gameID 560260
Adding process 1302 for gameID 560260
Adding process 1390 for gameID 560260
Proton: Upgrading prefix from None to 8.0-103 (/mnt/Games/Steam/steamapps/compatdata/560260/)
Adding process 1391 for gameID 560260
Adding process 1392 for gameID 560260
fsync: up and running.
wine: RLIMIT_NICE is <= 20, unable to use setpriority safely
Adding process 1393 for gameID 560260
Adding process 1396 for gameID 560260
Adding process 1398 for gameID 560260
Adding process 1401 for gameID 560260
Adding process 1410 for gameID 560260
Adding process 1423 for gameID 560260
Adding process 1429 for gameID 560260
Adding process 1442 for gameID 560260
Setting breakpad minidump AppID = 560260
Steam_SetMinidumpSteamID: Caching Steam ID: 76561198248711762 [API loaded no]
Adding process 1461 for gameID 560260
pid 1394 != 1393, skipping destruction (fork without exec?)
Game Recording - game stopped [gameid=560260]
Removing process 1461 for gameID 560260
Removing process 1442 for gameID 560260
Removing process 1429 for gameID 560260
Removing process 1423 for gameID 560260
Removing process 1410 for gameID 560260
Removing process 1401 for gameID 560260
Removing process 1398 for gameID 560260
Removing process 1396 for gameID 560260
Removing process 1393 for gameID 560260
Removing process 1392 for gameID 560260
Removing process 1391 for gameID 560260
Removing process 1390 for gameID 560260
Removing process 1302 for gameID 560260
Removing process 1301 for gameID 560260
Removing process 1300 for gameID 560260
Games still don't works 🤷
But for example I've try to launch a game through Steam Proton 8.0-5 via Steam from Flatpak now. How can I find here required libraries?
https://0.jaegers.net/?ae1611da37b8a25e#EFiVE6PGNBi4guHKZ56UKaWoGVoiZrf2GtsCDphEv95e