actually not, had to buy the DRM version from steam to try it with Proton Experimental (as most users reported it worked) but it is garbage... I would love if it had a linux build or at least a good wine/proton compatibility, a DRM-free version should be the best!
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)