I think people would enjoy a category like super Mario 64 where at every moon you go back to the odyssey!

I don't think people would really enjoy that, as it would be fairly monotonous and would be based solely on which moons are closest to the Odyssey.

This would be super slow and boring imo. It would probably be cool to see it routed, but after routing it no one would run it because of how tedious it would be.

Is there a way to mod the game to do that?

If people run talkatoo%, why don't people speedrun this