Games running through Steam crash on start

Hello,

I have happily playing games on Bluefin and recently rebased to Bazzite DX in order to take advantage of non-Flatpak Steam and Sunshine. Everything worked well for a day or two, until it did not.

Both of my currently installed Steam games (Half-Life RTX and Split Fiction) just crashes as they start. I did a sanity check by verifying the game files integrity as well as reinstalling, but it did not fix the issue. I also installed a third game that I knew runs on my machine (LEGO Builder's Journey) and it did not work either.

I ran the games with the PROTON_LOG=1 %command% launch options to produce logs but as they are 4K, 25K and 54K lines long I don't know what to look for. (The logs if you want to take a look)

Ah yes, when launching Split Fiction I have some Unreal Engine-specific error dialog named "Wine C++ Runtine Library" that reads

    
Assertion failed!

Program:
Z:\var\home\axel\.steam\steam\steamapps\common\Split
Fiction\Split\Binaries\Win64\SplitFiction.exe
File: ../src-lsteamclient/steamclient_main.c
Line: 357

Expression: "!status"

Press OK to exit the program, or Cancel to start the Wine debugger.

  

Clicking OK opens a new error dialog named "The UE-Split Game has crashed and will close". Searching for both error dialogs online did not bring anything useful (the second dialog seems to be extremely brings Windows-specific fixes).

If anyone knows where I should look, that would be greatly appreciated!

Edit: I forgot to specify that I also tried rollbacking to a previous version of Bazzite and that The Sims 4 installed with Lutris does work.

Edit 2: I did a sanity check by running a native game (Portal 2) and it crashed after the Valve intro video. Is it possible my Steam install is borked?

Resolution:

The fact that even native games would crash lead me to believe that maybe I borked my Steam install while moving folders between the Flatpak and native versions of Steam.

So I went nuclear: I closed Steam, rm -rf'd ~/.steam and ~/.local/share/steam, re-launched it, installed a game and launched it. It did not crash!

All this wasted time because I did not want to waste time re-downloading my games...

Now comparing the two outputs of ~/.steam before and after, I can see that many folders and files were missing.