What are you talking about, am I forgetting something?
Basic haki is the shield style "barrier" thing you're talking about, then stage 2 buso is hardening, where you actually bolster the limbs/weapon itself instead of "coating it" in armor, you make the actual thing it's used on armor itself (which is the black coating). Sanji has level 1 barrier buso, zoro and luffy have buso hardening (along with tons of others who are either top commander leveled, or who specialize it and are don sai+ leveled.
Ryuou as we know it is pushing the haki OUTWARD like an energy blast, not an armor or hardening.
Oden objectively had ryuou, he grew up in the country that literally invented it, and is the strongest mf'er there, and every single one of his scabbards had it, and the only person who could teach rayleigh it cuz it's wano based, is Oden, so he'd have to know it.
Didn't Kaidou said they all have ryuou, but it was just weaker than Oden's?
Honestly speaking, Kaidou is going down by a group effort. Luffy will eventually surpass Oden, but meh, not yet.