In my opinion Ashura is indeed advanced CoC but first let us explain what advanced Haki is in the first place cause people seem to be confused. Being particularly proficient in a type of haki is one thing, having the advanced version of that haki is another(take Luffy for example who has advanced CoO but still has a lot to learn about CoO) and being able to use that type of haki to it's utmost efficiency via "flow"(ryou) is a completely different thing. "Ryou" isn't advCoA it's just an advanced usage of haki which revolves around flow and control of haki(similar to chakra control in Naruto) and after mastering the "flow of haki" you can apply any type of haki into it and ppl assumed this is advancedCoA because most characters use it with CoA but in fact you can use Ryou with any type of haki.
Now going back to Zoro, it seems that Zoro while being very proficient and possessing a very powerful armament haki neither has the advanced version of it nor does he knows Ryou, but after training and obtaining Enma he's able to kinda use it via the swrod(which explains why having Enma seemed like a powerup while it is not) but he probably isn't using Ryou in his other swords which is why he's still not as good as Oden. I believe that just having CoC or even advanced CoC can't damage Kaido unless you utilize Ryou with it then wtf did Zoro do with Ashura in order to scar Kaido? Well as we already established before, Ashura is indeed an advanced version of CoC but it doesn't "flow", so when Zoro used Ashura with Enma, Enma made Zoro's CoC "flow" out of his body and therefore damaged Kaido.
In conclusion of the above in order for Zoro to damage Kaido he needs to use Ashura + Enma together, unless Zoro reaches full control of Enma and therefore is able to use Ryou freely now after his body understood the concept of it and also realise that he has CoC and use it with Ryou. THEN Zoro will be able to replicate what he did to Kaido in 1010 without having to resort to Ashura or unleashing Enma's full power(that would be reserved for a finishing move)
Now going back to Zoro, it seems that Zoro while being very proficient and possessing a very powerful armament haki neither has the advanced version of it nor does he knows Ryou, but after training and obtaining Enma he's able to kinda use it via the swrod(which explains why having Enma seemed like a powerup while it is not) but he probably isn't using Ryou in his other swords which is why he's still not as good as Oden. I believe that just having CoC or even advanced CoC can't damage Kaido unless you utilize Ryou with it then wtf did Zoro do with Ashura in order to scar Kaido? Well as we already established before, Ashura is indeed an advanced version of CoC but it doesn't "flow", so when Zoro used Ashura with Enma, Enma made Zoro's CoC "flow" out of his body and therefore damaged Kaido.
In conclusion of the above in order for Zoro to damage Kaido he needs to use Ashura + Enma together, unless Zoro reaches full control of Enma and therefore is able to use Ryou freely now after his body understood the concept of it and also realise that he has CoC and use it with Ryou. THEN Zoro will be able to replicate what he did to Kaido in 1010 without having to resort to Ashura or unleashing Enma's full power(that would be reserved for a finishing move)
