Good news is that the steam build (which is the only way to run it with actual proton for technical reasons, that's just how proton works) seems to support linux decently well (in the "doesn't break proton' sense), so once the full version releases, it should be good to go!
Weird, it worked very well for me!
And I doubt there's any actual DRM in it, you could probably just run it directly and it'd be fine (but you'd lose proton, as proton is intended to only be run from steam and has a lot of very particular requirements that you're basically not going to be able to handle by itself)