Plus, again,
@Gintoki you should not be comparing yourself to NPCs. You should be comparing yourself to other PCs. Because if you hold an unfair advantage over other players of equal level, then that means you can do territories that they can't, which means you can get to rewards that they can't, just cause MZ > everything.
So if anything, the MZ needs to be balanced, and then the Yonkou can get balanced. But saying you should be 10x stronger than any other PC just so you can go solo Yonkou islands, is ridiculous.
I get your point that nerfing you would put you at a disadvantage against Yonkous, but at least you'd be at the SAME disadvantage as other level 90 PCs. And then we can work on that disadvantage by either nerfing Yonkous, or their Commanders.
Cause tbh, I think what needs nerfing is their commanders, not the actual Yonkous (as you said). And imo, even canonically speaking, the difference between Kaido and King/Queen cannot just be 5-10 levels. We all know Kaido would literally roflstomp them both 2 on 1 in 10 seconds. Their difference should be quite significant. And by nerfing all of those Commanders, you'd now see the light at the end of the tunnel.
But clinging your completely unbalanced MZs just so you can challenge the even more unbalanced Yonko crew setups, makes no sense.