This is a quick piece of news. I have been willing to try out Sweet Transit (released end of July 2022) for a while as I kind of enjoy train-related simulations (OpenTTD is one of my go-to time wasters) and sadly until now Sweet Transit did not work properly on Linux with Proton - launching it resulted in a black screen while the sound could be hearrd. I just tried it again today and it looks like either a recent game update or a recent improvement in Proton Experimental have fixed it. You can now play it as you’d expect, here is a quick capture as I went thru the tutorial.
Note that the game is supposed to get a native Linux version later on, but since the game is still being actively developed, that’s not one of the top priorities of the team at the moment. If you don’t mind Proton, you can now consider this game for your Linux setup.