I like the idea of specific % categories (Like 30% or 50%) either in this fashion or as level-specific leaderboards. Right now in all categories I feel like you're only encouraged to go to the fastest levels with the fastest credits. While routing is a big part of speedrunning, I think players who are good at moons other than March and Assurance should be able to display that in a run. Death% doesn't actually require standard looting-play; 100% is so hardcore it doesn't feel beginner-approachable. I think it would be fun to have a category where it's optimal/required to actually visit the other moons in a more fast-paced manner closer to casual play.
I would advise against modding, especially on the Switch. I practiced by making several accounts with saves to start at each kingdom. When modding your switch the best you do is save a few minutes when you practice as apposed to this idea, and you run the risk of bricking and missing out on all your updates. I lasted a long time without modding. If you are scared to do it then please don't.