Hello @DGauze, we're tracking issues with game run with Proton in the Proton issue tracker, so I've transferred this issue.
From https://github.com/ValveSoftware/Proton/issues/5150#issuecomment-1001006474, it might be interesting to test if disabling Steam's shader pre-caching has an effect.
Apologies, in my googling I saw the other similar issues under steam-for-linux so I figured I'd post there. Noted.
And yes, disabling shader pre-caching seemed to have fixed it. Thank you very much!
Your system information
Steam client version (build number or date):

Distribution (e.g. Ubuntu): Arch
Opted into Steam client beta?: Yes
Have you checked for system updates?: Yes
Please describe your issue in as much detail as possible:
https://gist.github.com/DGauze/c4ceeffe9619f4cdb7bcc661bddf1a7f
When I try to click play, the game acts as if it's open but nothing comes up at all. The play button on steam has turned into the big blue stop button, implying that something is happening but it never does.
The error codes I've been getting are either:
So I've been having this issue as of late with 3 games in particular: Battlefield 4, Kenshi, and Warframe. These games have launchers of some sort.
I have timeshifted all the way back to a 3 month old snapshot and all of these games worked flawlessly. After updating off of that snapshot again, Battlefield 4 continues to work but the other two simply don't. I'm at a loss as to what to do, and any googling of this error online has left me empty handed as I tried ALL of their solutions to no success.
Steps for reproducing this issue: