Donkey Kong Bananza is probably my Switch 2 game of choice. Like it may not be marketed as such, but it's probably somewhere on par with Super Mario Odyssey in terms of game design and mechanics, and has the craziest ending sequence I've ever seen in a video game. It is a really solid 3D platformer, and does to Donkey Kong what Super Mario 64 did to Super Mario Bros/World.

The DLC is really fun too, though whether it's worth buying is almost entirely dependent on how much you get into Emerald Rush. Personally I found that mode incredibly addictive for the longest time, though it's definitely not for everyone.

As a general rule though, the Switch 2's library is kinda niche right now though. What games/DLC are worth it heavily depends on your taste in games.

Cozy/sandbox game? Pokopia could be a good choice.

Fan of the Zelda series in general? The upgrades for BotW and TotK are nice, as is Age of Imprisonment.

Prefer Kirby? Air Riders and the Forgotten Land upgrade are a good bet. More of a Mario fan? Well, there aren't as many options there outside of Mario Kart, though the Wonder upgrade has been pretty well received, and Mario Tennis Fever is a decent game.

Generally you'll find one or two niche spinoffs you'll really get into, though nothing on the level of a big new 3D Mario/Zelda/Pokemon/whatever game.

DKB was created by the Odyssey team so it makes sense that it scratches the same itch!

Galaxy 1&2 have visual upgrades.