Hello @ryuukk, it should be noted that Proton is a compatibility layer intended to be launched from Steam. While this issue tracker is mildly flexible when it comes to discussing the behavior of third party builds, your specific question is about a missing library with a third party build of Proton being run with a third party launcher. This kind of dependency would be provided by the Steam Linux Runtime - Sniper container environment with the mainline build of Proton 8.0.
This is the wrong issue tracker to get help with your specific library dependency issue.
proton 8.0x1 2023-05
Compatibility Report
System Information
I confirm:
Symptoms
Game launched with only a black screen at first until I switched to Experimental. Afterwards game works even with default Proton but has serious performance issues. The second area drops well below ~15 fps on my hardware, likely unplayable on the Steam Deck - I will post an update once I get to try it there.
Reproduction
Run game, maybe switch to Experimental if it only displays a black screen. Observe unexpectedly poor performance, especially visible while riding the stagecoach.
steam-1940340.log