If you've been holding off on Cyberpunk 2077, it's in a really solid state nowadays, and has a pretty dang good main story with lots of roleplaying options, and plays well with a controller.

Terra Nil is a cool relaxing solarpunk strategy/builder game about restoring the environment. Not sure how complete controller support is, but its rated playable for the steam deck (could be hit or miss).

The Mass Effect series supports controller, and they're pretty fun sci-fi RPG's with good characters.

Disco Elysium is a more text heavy RPG. I personally bounced off it due to its theme, but it's pretty unique, worth a shot if you click with it.