Not a good argument considering how little we have seen Luffy use ACoC since Wano.
Luffy failed to save Dr. Vegapunk because he wasn't strong enough and needed giants and the real Joyboy help to survive his encounter with the Marines and world government. It doesn't make any sense for Luffy not to use all his power against the marines and world government on Egghead Island.
Based on your argument, Luffy can no longer use ACoC or his ACoC skills are low and he can't control ACoC haki.
The "it was BM CoC haki" argument doesn't work here. When fodders were knocked out they had no idea what happened and assume it was CoC haki. Then Usopp used that opportunity to take credit for it and make himself look stronger.
Afterwards the manga told us it was Big Mom CoC that knocked them out.
With Zoro, it's a very different situation. The scenes were about Zoro using overwhelming haki and mastering enma. We see Zoro's haki (black lightning) knock out fodders. King tells us it was Zoro's haki.