Playing this on an external drive using Steam Flatpak. Launched game in GE-Proton9-13 (Flatpak) and the game crashed after a few seconds. Switched to Proton Experimental and it worked with very minor stuttering at the start but game has been running fine since. Game should run best using vanilla settings and no tinkering. I've not tested multiplayer so far but I will put in feedback here as soon as I do.