Just a compare and example, I take both profile pages of AllMight(the strongest MHA character) and Mihawk from OSB site:
Info what we need:
AP: City lvl+
Speed: Hypersonic+
Durability: City lvl+
This is just a check up, but this are the infos for right now who are important.
Now Mihawk:
Info what we need:
AP: SMALL CONTINENT lvl+
Speed: Relativistic with light speed+
Durability: small continent+
OSB is just a example, but we already can clear see a huge big gap, a gap who is enough for Mihawk to stomp the whole mha verse
AP wise, Speed wise, durability wise, he is league above anything in MHA, combinate or not he stomp the whole verse.
Mihawk as top tier in one piece verse by scaling don´t gonna lose to a verse like MHA lol.