I think Oda or one of the assistants fucked up the last dialog. I think Sanji meant "this overpowered Haki" or that his CoA is boosted with CoC.
When Sanji says "Armament is not enough" -> That's identical to Luffy unlocking ACoC right before Kaido. CoA by itself is not enough. He needs CoC.
But then he says this overpowered CoA, when the entire time they're talking about CoC and we see a CoC burst. Maybe he means CoC-boosted CoA, but I don't think it's ACoA.
It's similar to what happened with Zoro.
Sanji didn't get that he has CoC, so he though he was using just very strong CoA (he even said like "I think that another way to beat you, without having CoC, is to beat your ass so many times that you beg to die").
Killingham noticed that with his regen slowing down, and tried to use the Omen armor, which can only be destroyed by advCoC, to counter the unaware Sanji.
In the end, Sanji, still thinking he was using just CoA, coated his leg and defence with as much haki as possible -> that resulted in a massive CoC burst and a coated advCoC kick that shattered the helmet.
Basically, this is not even full control advCoC Wanji

