Every top tier has bad feats, kaido jabbing to rocks, bm constantly getting memed, kizaru getting pushed around by Marco, kuzan bleeding to jozu, garp getting dropped to 1% hp from a basic stab, sengoku not being able to damage pre time skip luffy, etc. All the top tier in mf were fighting way harder than mihawk. Mihawk had no real narrative place as wb was the only one he cwould completely fodderlize if he fought seriously. All the admirals had more narrative purpose to fight wb which is why they all did at some point. Garp sengoku and mihawk had less narrative purpose to fight him which is why none did. If mf was written with all of them being serious the wb pirates would have gotten wiped out in 10 minutes amd luffy would have died so mf top tiers had to be held back. All top tiers have bad showing because oda doesn't make his top tiers complete monsters but have quirks about them that let's other characters take advantage of them. Mihawks is he only uses necessary power to fight his opponent. He fights down to his competition which is why a east blue zoro could have a full fight with him and didn't get instantly fodderlize. Oda gave him that type of personality to preserve him going all out while still keep him respectable as he will always fight to the level of competition. That's like saying kaido looks bad because his quirk is letting characters hit him to judge how worthy they are. Mihawk is never going to just go all out and he's always going to fight to the level of his opponent that's his personality and it doesn't make him look bad for doing it. Oda can't let mihawk go all out because him doing that caps the story. And in mf if mihawk took out Vista wbp lose a huge piece of thier army and if he took out luffy the story is over. Mihawk couldn't take out either for narrative purpose so oda used the quirk in his personality to make him fight to their level just to progress the story. It's not that serious anybody with half a brain knows if mihawk was serious he would have easily killed luffy or Vista but not only could he not for the story but it isn't in his personality to just go all out and kill someone.
No top tier in marineford were put in situations where they looked weak and no character in general goes all out off the bat
Kuzan didn’t go all out but wasn’t put in situations where he was chasing after Luffy just to be stopped by vista and crocodile talking shit
Hell it took just about everyone to stop Sakazuki from getting luffy
Borsalino was casually bodied luffy every time they “clashed”
Even within the warlords none of them were done that dirty either. Everytime Doflamingo and Hancock were doing anything they were never bitched