I literally could not figure out how to get my GOG copy of Fallout 3 running on my Steam Deck, nor could I find anyone else online discussing what would make it work. I’m sure if I’d wanted to put in the work that I could have gotten it running. I was feeling lazy though, so I bought a copy on Steam. It works without any configuration.
Valve has taken a Linux PC and given it a handheld console form. I couldn’t be happier with it.