Zoro acquired AdvCoc at the same speed Luffy did
what you are trying to say is that there is some imaginary rule about “you must have a certain level of regular CoC to use AdvCoC”
and there is no such rule. If Oda were to create that rule, he would have to then explain why Rayleigh, Kid, Boa and Doflamingo dont have AdvCoC
so Oda doesnt make any rules around it so that Luffy can just obtain it at will. Yamatao can just simply be revealed to have AdvCoC without the need to explain how Haki master Rayleigh doesnt have it. And when the story requires it, Zoro obtains it as well to tame Enma
In your head Zoro got it too fast but in the manga the speed of obtaining it is never stated