Now this is some seriously cool software and I love to see it. PartyDeck is a new tool that can help you run various games in local split-screen, even if they don't actually support it.
Seems really cool. I haven’t gotten to test it out yet, so I’m not sure how well steam game licenses work with it yet
Steam has joy-con support built in! Depending on the game you want to play, you might be able to get away with two half-controllers.