Again stop capping before either looking it up or doing research. In the episode of luffy where they showed coby as a captain and helmeppo with the new vice admiral they literally showed coby reading the vice admirals mind.
He also did this in marine Ford when he first got it
Officially he still only shares the same rank as Jack or Queen. Granted, he does take over the crew and gives out orders when Kaido ain't around like a true right hand but he also isn't really a vice captain.
I'm pretty sure the only reason for that is that King is the only calamity that can fly with Kaido lol
Akainu and Kuzan shared the same rank and Akainu defeated Kuzan, Mihawk and Buggy share the same Warlord position and ofc Buggy neg diffs him what are you talking about, sharing a rank isn't something to scale with, all SHs share the same rank in the crew as members and obviously Usopp neg diffs all of them 1v9...
It is so funny some Zoro fanboys do not understand the importance of coc splitting heavens. Kaido said only very few people can use advanced coc. And out of those few, fewer can actually create an attack so powerful that it reaches heavens. Luffy canonically is shown to have the attack power on the levels of top tiers.