I've actually been staying on Wine 5.14 (Staging) on Arch myself - any versions higher than that cause the 64-bit version of the game to crash for me (I haven't tried the 32-bit version). Could you try confirming that, @ColdZero?
Actually, I can take credit for that! The StartupWMClass is used for associating windows to a specific application. On Linux desktops, that's used to allow for the tracking of application start-ups, among other things. You can read more about it here. Needless to say, most .desktop files will have this, and it can be important for making applications behave as expected - for instance, Latte Dock.