Dwarf Fortress (975370)

Proton version: 7.0-6
OS: Ubuntu 20.04.5 LTS (64 bits)

Ok, this may be a weird one, but bear with me, please.

So, I've been running Steam's Dwarf Fortress with proton for almost two months without any issue. But suddenly, last weak, the game started to not boot at all. You click the 'play' button on steam, and just immediately crashes. Digging on the system log, this is what's going on:

Could not connect to X session manager: None of the authentication protocols specified are supported
Could not connect to X session manager: None of the authentication protocols specified are supported
GameAction [AppID 975370, ActionID 2] : LaunchApp changed task to ProcessingInstallScript with ""
Inconsistency detected by ld.so: dl-call-libc-early-init.c: 37: _dl_call_libc_early_init: Assertion `sym != NULL' failed!
GameAction [AppID 975370, ActionID 2] : LaunchApp changed task to SynchronizingCloud with ""
GameAction [AppID 975370, ActionID 2] : LaunchApp changed task to SiteLicenseSeatCheckout with ""
GameAction [AppID 975370, ActionID 2] : LaunchApp changed task to CreatingProcess with ""
GameAction [AppID 975370, ActionID 2] : LaunchApp waiting for user response to CreatingProcess ""
GameAction [AppID 975370, ActionID 2] : LaunchApp continues with user response "CreatingProcess"
/bin/sh\0-c\0/home/javi/.local/share/Steam/ubuntu12_32/reaper SteamLaunch AppId=975370 -- /home/javi/.local/share/Steam/ubuntu12_32/steam-launch-wrapper -- '/home/javi/.local/share/Steam/steamapps/common/SteamLinuxRuntime_soldier'/_v2-entry-point --verb=waitforexitandrun -- '/home/javi/.local/share/Steam/steamapps/common/Proton - Experimental'/proton waitforexitandrun  '/home/javi/.local/share/Steam/steamapps/common/Dwarf Fortress/Dwarf Fortress.exe'\0
Game process added : AppID 975370 "/home/javi/.local/share/Steam/ubuntu12_32/reaper SteamLaunch AppId=975370 -- /home/javi/.local/share/Steam/ubuntu12_32/steam-launch-wrapper -- '/home/javi/.local/share/Steam/steamapps/common/SteamLinuxRuntime_soldier'/_v2-entry-point --verb=waitforexitandrun -- '/home/javi/.local/share/Steam/steamapps/common/Proton - Experimental'/proton waitforexitandrun  '/home/javi/.local/share/Steam/steamapps/common/Dwarf Fortress/Dwarf Fortress.exe'", ProcID 47107, IP 0.0.0.0:0
chdir /home/javi/.local/share/Steam/steamapps/common/Dwarf Fortress
ERROR: ld.so: object '/home/javi/.local/share/Steam/ubuntu12_32/gameoverlayrenderer.so' from LD_PRELOAD cannot be preloaded (wrong ELF class: ELFCLASS32): ignored.
ERROR: ld.so: object '/home/javi/.local/share/Steam/ubuntu12_64/gameoverlayrenderer.so' from LD_PRELOAD cannot be preloaded (wrong ELF class: ELFCLASS64): ignored.
ERROR: ld.so: object '/home/javi/.local/share/Steam/ubuntu12_32/gameoverlayrenderer.so' from LD_PRELOAD cannot be preloaded (wrong ELF class: ELFCLASS32): ignored.
ERROR: ld.so: object '/home/javi/.local/share/Steam/ubuntu12_32/gameoverlayrenderer.so' from LD_PRELOAD cannot be preloaded (wrong ELF class: ELFCLASS32): ignored.
GameAction [AppID 975370, ActionID 2] : LaunchApp changed task to WaitingGameWindow with ""
ERROR: ld.so: object '/home/javi/.local/share/Steam/ubuntu12_32/gameoverlayrenderer.so' from LD_PRELOAD cannot be preloaded (wrong ELF class: ELFCLASS32): ignored.
Inconsistency detected by ld.so: dl-call-libc-early-init.c: 37: _dl_call_libc_early_init: Assertion `sym != NULL' failed!
GameAction [AppID 975370, ActionID 2] : LaunchApp changed task to Completed with ""
Steam: An X Error occurred
X Error of failed request:  BadWindow (invalid Window parameter)
Major opcode of failed request:  20 (X_GetProperty)
Resource id in failed request:  0x68005c5
Serial number of failed request:  31
xerror_handler: X failed, continuing
Steam: An X Error occurred
X Error of failed request:  BadWindow (invalid Window parameter)
Major opcode of failed request:  20 (X_GetProperty)
Resource id in failed request:  0x68005c5
Serial number of failed request:  31
xerror_handler: X failed, continuing
Steam: An X Error occurred
X Error of failed request:  BadWindow (invalid Window parameter)
Major opcode of failed request:  20 (X_GetProperty)
Resource id in failed request:  0x68005c5
Serial number of failed request:  31
xerror_handler: X failed, continuing
Game process removed: AppID 975370 "/home/javi/.local/share/Steam/ubuntu12_32/reaper SteamLaunch AppId=975370 -- /home/javi/.local/share/Steam/ubuntu12_32/steam-launch-wrapper -- '/home/javi/.local/share/Steam/steamapps/common/SteamLinuxRuntime_soldier'/_v2-entry-point --verb=waitforexitandrun -- '/home/javi/.local/share/Steam/steamapps/common/Proton - Experimental'/proton waitforexitandrun  '/home/javi/.local/share/Steam/steamapps/common/Dwarf Fortress/Dwarf Fortress.exe'", ProcID 47107 
ThreadGetProcessExitCode: no such process 47109
ThreadGetProcessExitCode: no such process 47108
Uploaded AppInterfaceStats to Steam

Now, seeing that, I assumed there was some issue with my Nvidia card (NVIDIA RTX A2000) drivers, so I tried to reinstall them again. Nothing, same result, everything else, every other game, every other tool, seem to be playing nice with my card.
I've tried with, quite literally, every version of Proton that Steam allows, and the result was the same.
I've tried to uninstall and install the game, same. I've tried to purge Steam (plus deleting ~/.steam and ~/.local/share/Steam) and install again, same.

And here comes the weird part: I just logged in to a different use (both are admins), installed Steam and Dwarf Fortress ... and it runs ok from there (actually, it runs quite better because all the work I've done actually updating my drivers, ha). Then, if I switch back to my main user account... the game still doesn't run.

I have tried to delete and reinstall everything related to steam or proton I could find in my home directory, but nothing seems to do the trick. I don't think it can be a drivers issue, because it would affect my other upser account.

Start with the Steam and Proton launch log in the report, comparing the failing main user account with the working second account. No source file or test is named; done means identifying the user-specific cause of the launch failure and confirming that Dwarf Fortress starts successfully for the affected account.