I spent very much time trying to get this game to work on my modern pc. Tried different Proton versions and launch parameters. I tried changing graphics driver version but the result was still the same: unit stuttering and eventually crashing. My laptop running Ubuntu didn't have this issue so I think this depends on your hardware. Finally trying to rule out CPU issue, setting taskset -cp 0 [Pid] (where [Pid] is the Game.exe's ID) to terminal when running the game solved the issue. The game's affinity list was on my case 0-15 and that causes issues for such an old game. That command sets the game use only one. The drawback is that it needs to be given every time the game is launched but hey at least it's now very well playable on modern hardware. I verified this to work with GOG release using Lutris launcher and also using custom Proton version on Steam. Very likely works equally as well with the default Proton version. Don't forget also to change the resolution from the game's config.cfg file if you are playing with modern display. Further instructions can be found online. So glad that I'm finally able to play this classic RTS game on my Linux machine.

TL;DR. Set taskset -cp 0 [Pid] if you are playing with modern multi-processor PC and experiencing weird bugs and crashes.