The game runs with no issues or crashes at all (played several games for 3+ hours straight), providing the same experience as it does in Windows, including multiplayer which works flawlessly.

If you get "Compatibility tool configuration failed" error - I did and had no idea why - just reinstall Proton and Steam Runtime. If Steam doesn't let you to, delete local files in the ./common folder on your own, and get them back by verifying integrity of the files in Steam.