I agree that too few levels on Mario Maker 2 feel like they could be real Mario levels. Sometimes that's part of the fun - thinking outside the box, breaking the mold and whatnot - but quite often it feels like they're designed out of spite.
The beauty of Mario's level design is that it's so rare that you're ever blaming the game, or the design, for your mistakes. I can only think of one instance of a Mario game getting me into a controller-throwing rage because the camera, the controls, or the timing, or an enemy appearing out of nowhere, was the reason I was dying. That, to me, is the sign of a good game - when, even when you keep losing, you know it's because of your error, not because the mechanics don't work properly, or the design is conspiring against you.