I have this idea in my mind that Supreme Kai (our “Shin”) is stronger than all the other universe’s Supreme Kais because Beerus was so monumentally bad at his job that Shin basically had to take up the role of destroyer when everything went to shit.
As far as we know, beings like Majin Buu didn’t exist in any of the other universes (he might have existed in universe 6 but it doesn’t look like it. Maybe Champa actually did his job or he was just never created)
Idk, I just think it would be really interesting to see the power levels/fighting power of all the Kais. We know Beerus is one of the strongest destroyers; maybe Shin is one of the strongest Kais?