How to force Linux games to use Steam Proton?

Sometimes it can happen that a Linux game doesn't work that well (or at all), but now we can use Steam Proton to force a Linux supported game on Steam, to use Proton.

To use this option we have to enable Proton for our whole Steam Library.

1. Click on the Steam menu and go to Settings.
2. On the left side choose Steam Play.
3. Here just check both options: Enable Steam Play for supported titles and Enable Steam Play for all other titles
4. Press OK and restart Steam.

Now we can enable Linux supported games to install and play via Proton. The trick is simple.

1. Go to Library view in Steam, and right click -> Properties on the game you want to install and play via Proton.
2. Just check at the bottom option: Force the use of a specific Steam Play compatibility tool

With that we can add the version of Proton we want to try. I recommend some stable (non-beta) version, unless you know what you are doing.

Note: This method works for non-Steam games too, that we add to our Steam Library!