Monster Hunter: World + Iceborne was on sale so I snagged it and I've enjoyed it quite a bit. Runs just fine on the deck and even though the game is clearly intended for multiplayer it works totally fine as a solo game.
The main issue I had with the game is that there's no pause button (as mentioned, it's a game oriented towards multiplayer) which isn't really compatible with my current life but with Decky Loader and the Pause Game plugin installed I can easily pause the game mid-quest without worrying about failing the time limit.