A quick search says it should be fine to use your existing saves: https://steamcommunity.com/app/377840/discussions/0/4739443320533222806/
Moguri mod works great on the Steam deck. It’s a bit of a learning curve to get it installed, but there’s a guide that will take you through the entire process, and it will teach you some about the more niche features of the deck.
So Wolfenstein is fair game because that’s clearly satire, with roided up, mecha Nazis, but this is bad because… robot Thatcher? Sure, that makes sense.