Whatever you do, don't buy the overpriced "new versions" of BOTW and TOTK. Just pay the $10 to patch your old copies. Not sure why they're even selling the new versions like it's some sort of new remaster.
The new versions improve the framerate substantially, and the draw distance is better (structures at the mid-range of distance won't be blurry) but they aren't that impressive. I've seen BOTW look WAY nicer on emulation.
That said, even just as a $10 framerate patch, they did okay with this. I'd gladly pay $10 for a Bloodborne framerate patch, for example.
Mario Kart 9 didn't take long to wrap up the single-player content for, looking for something else to do. Could try to 100% Mario Odyssey (only 3D Mario I didn't 100%) but I don't even know what 100%ing that game looks like. Getting all the moons seems kind of ridiculous if there are really like 900 of them. I've got a couple of worlds I didn't even touch, though, when I initially beat the game with 150 or so moons. Mario Odyssey looks really nice on the Switch 2 (with a free patch, which is a plus) but I don't even know where to start with it. I guess just keep collecting moons until it stops being fun?