Btw. as I'm on Arch, I did try to fix this by installing two AUR packages and did launch Steam with steam-native.
Not sure if this help, too. I got this console crash report, too:
[Console Output: Warhammer 40,000: Dawn of War III: Crashes ingame #285190](https://gist.github.com/tr37ion/4fd6ad3d740c164ea8a39aa853e6450d)
Multiplayer games crashes as soon as it starts. (Proton 6.3-6 & Proton 6 Experimental)
Compatibility Report
System Information
I confirm:
[x] that I haven't found an existing compatibility report for this game.
[x] that I have checked whether there are updates for my system available.
`PROTON_LOG=1 %command%:
steam-285190.log
Symptoms / Reproduction
Opening a multiplayer game and trying to chat or click mouse around crashes the game after some random seconds.