So since this new DK game is what the 3d mario team has been working on, I'm guessing it's the reason why we haven't gotten any odyssey DLC or anything. Before the direct, I actually had a theory about what I thought the next 3d mario project would be like.
A lot of recent nintendo projects have been sharing a lot on DNA recently, sharing similar structures and gameplay loops and design philosophies. I definitely felt similarities between how odyssey's moons were set up and BotW's Koroks, both having changable costumes, and the flags and shrines in each game functioning as warp points. Now this new DK game seems to be incorporating destructible terrain, which will probably allow you to skip a lot of segments like how the runes let you skip puzzles in BotW. So i'm predicting a sort of "breath of the wild-ification" of the next mario game. Specifically, a focus on physics and environment interaction.
Wonder already started playing with this, there were several intractable physics objects in the game like the falling pillars you could push and the rolling rocks. Mario has never really had complex physics before, so the way the pillars actually interacted with level geometry as they landed really stood out to me. And it also had a lot more elemental interaction too, I'm think about Elephant mario having unique interactions with water, the popcorn enemies interacting with fire tiles, it even had the same metal conducting electricity mechanic from BotW. Mario had been adding more interactivity between level elements since Maker, but there is definitely some zelda influences in how wonder incorporates it.
So I'm thinking in the next mario game, you'd be able to interact with physics based objects, maybe in some kind of being able to pick things up and throw them way, or something silly like rolling them up Katamari style. And items will have more material/element based interactions, maybe Mario will have something similar to the elemental pultergust powerups in Luigi's mansion or he'd be able to change what material he's made of through something like the metal cap.