Everything I said is manga facts. I posted chapter scenes/pages to back up my claim. You are the one posting headcannon.
Swordsman grow stronger by learning to control dangerous/cursed/different swords. Which are just tools for the swordsman to use. A skilled/great swordsman bends to sword to their will and will be able to apply their skills, strength and power to any sword.
He doesn't need enma to use ACoC. That's just the tool he used to grow stronger. It like training with a weighted vest. Zoro stated he would be stronger by the time he is used to it.
Here's Zoro using ACoC with just Sandai.
He doesn't need enma to use KoH style. That's just what the manga calls it when he uses large amounts of (smoking/steaming) CoA haki and ACoC. That will serve a purpose later on after Zoro forge black blades. We will know when he is using blackened haki with his black blades.
Zoro knows about CoC. He just didn't know he had it. Remember, you can't learn CoC, just unlock it. It's like Luffy having CoA but not knowing it can be flowed and him going from that to internal destruction haki.
Ryu is not CoC. Luffy just realized he can release and coat his attacks with CoC. Similar to releasing and coating his body/weapons with CoA.
The following post explains Ryu is not a Wano term for CoC. It's just the term to use for CoA.
He doesn't need enma to use ACoC. That's just the tool he used to grow stronger. It like training with a weighted vest. Zoro stated he would be stronger by the time he is used to it.
Here's Zoro using ACoC with just Sandai.