Valve recommends Proton 7.0-6, but in my experience this version of proton breaks the 30fps cap, either by unlocking the game entirely or by adding constant stutter so I dont recommend this version. Toggling the ingame fullscreen option may also break the 30fps cap, unlocking the game speed and making the game run way faster than it should. Use the performance overlay to make sure your game is running at 30 and you shouldn't have any issues.