If you’ve never played Super Space ________ and you’re looking for local split screen games I highly recommend it. It’s an amazing blend of competitive and cooperative design that’s always fun and chaotic. And it’s free! But it’s not on Steam since it’s a collegiate project. Link
From what I’ve heard of Lovers in a Dangerous Spacetime, that’s a very similar game but I haven’t tried it.
Yeah, I’m uninterested in buying any new controllers until they make a Steam Deck without the screen. I’m convinced no controller has ever been more comfortable or more versatile than the Steam Deck