Looks like Luffy is busting up the wall of the backside, I don't know what else could it be within that context.
ID CoA finally getting a DC feat, when we only had that tree feat in Wano up until now is really appreciated. If Oda is really cool, he first lets Luffy use ID CoA, where he does not break the wall and makes him use ID CoA enhanced by CoC to then destroy the wall. Would get us a rough estimation of the difference in power at play.
Assuming that hint is about Luffy's haki ofc.
Edit: If he goes for ID CoA and then advCoC, we could also see where Sabo's dragon breath fits into it.