Amnesia: The Bunker has been amazing so far. It has been checking all the boxes for effective, fun-to-play, horror. The gameplay loop and systems make it so it's easy to pick up and put down, where each adventure into the bunker feels like you are breaking some new ground before returning back to the central saferoom. The sound and level design are also perfect. All I can say is that it really does feel like I am in a sprawling WW1 bunker that has a horrifying eldritch monster burrowing in its walls.

Yep, for steamdeck your options are to install windows or to stream. Greenlight is a good linux application that handles the streaming better than the website imo. It can also do remote play if you have an Xbox, which generally has much lower input latency.

It is currently not possible. Games installed through GamePass have some kind of Windows compatibility layer which cannot be run by any wine or proton versions. At least not yet.