Mihawk could have oneshot Luffy with his very first attack if he wasn't holding back.
Mihawk even had his eyes closed and was bragging about Luffy still being in his range.
Mihawk wasn't measuring WB strength. He was testing to see if a Yonko can be easily hit with his YC protecting him. One of the main job of the YC is to protect their Yonko. Yonko hardly ever leave their territory so even though WB was close to them he wasn't as close as it appears.
Jozu used his diamond defense, a top tier defense made from diamond, one of the hardest matter in the manga, to stop Mihawk nameless hakiless attack. Requireing diamond to stop a nameless hakiless attack is anything but a sign of weakness. It showed how powerful Mihawk is and a type of defense needed to stop semi-serious attack.
Jozu was never hurt in the manga while using his diamond defense. He was only beaten by admiral when he wasn't using his diamond defense and was distracted. His diamond hardness doesn't go down just because he's not a top tier. That's not how things work.
I'm talking about Vista. Mihawk easily fought him without focusing on him for part of the battle and Vista could not hit him. In every other series that is shown as a sign of strength but somehow in One Piece fans want us to believe that is a sign of weakness even though no other character has been able to recreate that feat.
It's not the fact Mihawk cut through a iceberg the size of a mountain range, that required 2 top tiers to create (yonko and admiral). It's the fact he did it so effortlessly and easily. He did that while playing with Luffy. We've seen other people cut mountain size objects in half but all of them had to put much more effort and power into it. Mihawk using a little bit of power is equal to other characters using a lot.
His strength was hyped up beyond the combined powers of 3 admirals. Luffy stated Mihawk was too strong to fight during Marineford but not 3 admirals at the same time. That's not headcannon, that happened. Oda could have had Luffy make that statement about the 3 admirals and say nothing about Mihawk, but he didn't so get over it.
What is a YC5 level? That's just a term readers created. WB has 16 division commanders (YC). They all hold equal authority with Marco being the right hand man. Marco is the only one you can argue being stronger then Vista.
The problem that Mihawk face is for years fans believed top tiers couldn't be evaded, blocked, countered, hurt or blitzed by anybody other than top tier. Regardless of the level or amount of power they use. Now since that was proven to be false, fans make every single excuse when that happen to anybody except Mihawk. All they end up doing is just embarrassing themselves and show how bias they really are.