There is no such thing as Advanced Conquerors Haki. It's called infusing Conquerors Haki in his attacks and that's exactly what Oda meant.
And yes, Oden was a level lesser than Whitebeard and Roger. Exactly like Yamato is a level lesser than Kaido and Luffy here.
He stated and I quote."Only a handful of the strongest can. Not a dead man walking."
Meaning Luffy, who is that close to dying right here, might have the potential to do that, as Kaido acknowledged in Kuri. But he isn't going to reach it since he already has one foot in the grave.
You can use CoC in an attack without infusing it properly to destroy your opponent, that is the distinction between base and adv CoC. Luffy has been using moments of base CoC in his attacks since punching Blackbeard in the
pre skip.
Yamato likely doesn't have adv CoC either.
Kaido was calling him a dead man walking because he was going to kill him before he'd have the chance to unlock it years and years down the road, not that he was too nerfed to unlock it.
Kaido was directly saying Luffy was not "one of the strongest" with that statement, that is the key point.
But according to you "one of the strongest" Zoro should "be happy" with a small scar in Kaido's mind. I don't know how many gymnastic flips you have to pull off in your head to get to that conclusion.
Yamato says Luffy is the ONLY ONE who can challenge Kaido, she is not "one of the strongest", neither is Zoro, she puts Kaido and Luffy on that tier, no one else.