But it isn’t equal buffs.
Yamato and Zoro ALREADY have ACoC.
So King’s getting buffed more than anyone else here, and his durability is already leagues ahead of theirs.
With his speed, he’s also one of, if not the fastest one here, and with future sight he would be even harder to hit than he already is.
King was a problem for Zoro and he barely used Haki at all, and had no advanced forms.
Add all 3 advanced Haki types and complete mastery, and he’s #1 in the verse. Lunarians are the strongest species, and he has the strongest possible Haki, and a great devil fruit.
The only thing that could beat him would be a Lunarian with all mastered Haki and a better devil fruit