I'll admit i'm mainly asking this beacuse me and some other people were planning on trying to race the game peach-only without warps, but i'm honestly serprised there aren't all levels versions of the single character runs. I'll admit I don't run enough to be able to say much on the matter, but I was just curious about why single character all stages isn't a thing?

It's on the category extensions page
https://www.speedrun.com/smb2ce