Ryuo is the barrier haki you mean? For god sake man, just say Barrier haki... geez
CoA:
1. Invisible regular haki -> Luffy touches Caesar and Tashigi in Smoker's body
2. Hardening -> Everyone and their mother
3. Barrier -> Rayleigh, Hyogoro, Sentomaru, Boa's sisters, Luffy, the Admirals
4. Internal Destruction (wrongly called Ryuo by the community) -> Rayleigh, Luffy, potentially Zoro, potentially the scabbards, maybe Kaido (with Thunder Bagua, since Ragnarok is CoC)
I think he's talking about number 4.
CoC:
1. Knocks fodder (or at least people sufficiently weaker than the user) out
2. Used in attacks -> Roger and Whitebeards in their clash, Kaido in Ragnarok and maybe (?) Thunder Bagua, maybe Ashura (unless it's type 1)
At this point CoA types 2 and 4 and CoC type 2 look exactly the same. You could argue that haki leaking from a blade is a sign of CoC type 2, but then sometimes Zoro leaks haki too. Confusing af.