Mine has to be Dragon Quest: Rocket Slime, a DS spin off of the Dragon Quest series that sees you playing as a slime operating a tank and rescuing the people from your town. You run around the overworld, collecting items to use as ammunition and saving money to upgrade your tank. The art and music are just as great as you’d expect from the Dragon Quest series. It made fantastic use of the DS’s dual screens. It’s also written for a younger audience, so a lot of it is just really silly and fun! Try it out for sure, I’m so sad there’s no sequel :(
I haven’t played Planetside 2 in forever so I could be wrong, but I was playing that game on my shit box I made in 2011. Planetside 2 would probably run great on steam deck, but because it’s an FPS MMO (a mature MMO at that, lots of ) I think you’re gonna get your ass blasted by the whales if you’re not using a mouse for aim. That’s pretty much the only heads up I have on the game though.
Noted - I’ll give it a shot in my docked setup!