Taking place in a single fantasy world means, from my point of view, that it shouldn't really be a multiverse, but instead a roleplay simply for this epic world we all add ideas to. That would also help wrangle in the characters to a more consistent level rather than have Super Saiyans existing in the same setting. There would always have to be a hand wave why they couldn't help out in the lower tier fights otherwise.

Our setting could allow a lot of different paths that magic could take so characters like Evvie can still exist, or people with unconventional magic. Basically, a sort of magical evolution can take place in idviduals.