Ive tried so many, but right now I am on Proton Experimental.
It's been working, hilariously, since I made my post.
It looks like the issue is with how it updates. The errors I get are all failed to load .pak. the fix usually requires me to validate the integrity of game files, where it inevitably finds some files that fails validation and redownloads them. The irritating thing is that that doesn't always work. Sometimes it just stays broken.
This last attempt at fixing it I validated(needed to download some failed files), completely exited steam, relaunched, new update, exited steam, relaunched, new update, exited steam, relaunch and finally it had no updates. I did one last validation and launched and its worked since then.
Edit: so it said there was an update after my last session. I updated. The next time I launched (5min ago) I got an error:
I did the "verify game files" and wouldn't ya know it. Failed to validate 2 files.