So when you say the entire MHA verse, I’m just assuming you mean like literally every character in their primes lol.
And let me count the ways that Mihawk loses this.
First off, if we put Mihawk into the current MHA verse and ask him to solo, he loses. Current Shigaraki and Gigantomachia are too overpowered. Shigaraki can literally remove Dressrosa from existence with one finger. He is as physically strong and durable as All Might, has ridiculous regeneration, and he has other quirks that would make him by himself at least an upper mid diff for Mihawk. And that’s just one character.
Gigantomachia himself is around Jozu level. He didn’t even flinch from Dabi’s flame, his physical strength is probably even higher then Jozu’s, he has practically flawless stamina and other overpowered quirks that let him do all kinds of silly ass things...Gigantomachia is just silly. He utterly neg diffed pretty much every hero by himself, just from trying to run straight forward.
There are other plenty overpowered MHA characters as well that would prove troublesome for Mihawk. Re-Destro in his 80% stress form can obliterate multiple city blocks just from swinging his arms (and he can go up to 150% power in his Krestro suit), Endeavor’s firepower arguably exceeds any heat based power in OP (seriously Endeavor can probably kill any OP character minus people like Kaido or Big Mom who’s durability isn’t fully understood), the High End Nomu’s are all very dangerous for numerous reasons, etc...
Put just these 4 together and they have a serious chance at beating Mihawk. And this is just the current MHA verse. We haven’t even talked about All Might and AFO in their primes.
People massively overrate the speed of OP characters in versus discussions. Mihawk can react to light speed, but that doesn’t mean Mihawk blitzes every MHA character, it just means he doesn’t have trouble reacting to them. Mihawk is actually not that fast in combat, as pre TS Luffy who could not perceive Kizaru was dodging him left and right. There’s no reason to assume Mihawk speed blitzes or that he can defeat a literal army of these characters all trying to take him down at once lol.
The MHA verse wins while most of their combatants are not even present.