Yes, you can use Proton with any Steam game, including non-stream games.
Yes, you can use Proton with any Steam game, including non-stream games.
It's feasible, though it varies by game and additional conditions.
Yep. Here's a fairly comprehensive guide on Reddit: TL;DR: Add the game Game properties > Compatibility > Force the use of a specific Steam Play compatibility tool > Choose a Proton version, the default is probably good That should be where it ends but Steam doesn't manage the dependencies itself (why???) so you also need: Library > Games and Software > Tools > Install the version of Proton you selected and Steam Linux Runtime Play