I've seen it stated as some kind of common consensus that "Ryuo is just the Wano name of Armament Haki like how Mantra is just the Skypiea name of Observation Haki"
This statement isn't true. Mantra is just the Skypiea name of observation haki because there's a panel in the manga saying just that.
On the other hand, the panels supposedly saying Ryuo is just Armament haki is this.
As you can see, Ryuo is Armament Haki focused on FLOW. As in, Just armament haki isn't a thing in Wano. By that I mean there is no name for just armament haki. It becomes Ryuo when the armament haki FLOWS.
This doesn't mean people literally can't use basic armament haki in Wano. They just don't have a name for it. What they actually care about to name is FLOWING armament haki. And why do they do this? Because they are all Swordsmen.
Armament haki is used for fighting. And everybody in Wano fights with swords. Even Kawamatsu who is introduced as a sumo wrestler still fights with swords. Therefore, by default, armament haki MUST be used on swords for Wano people to be useful in combat.
And making your Armament Haki FLOW into your sword is Ryuo.
So basically, Luffy having basic armament haki isn't a concept people in Wano have a name for since nobody fights without weapons in Wano. Hell in Ringo, people are literally given swords at birth just to emphasise how much everybody is a swordsman. Of course even Wano people need to know basic armament first before they can make it FLOW but since nobody uses basic armament in combat, there's no name for it. When the Haki can FLOW into your sword, then it can be used in combat and so then it becomes Ryou.
Even when Hyogoro beats Alpacaman unarmed using "barrier haki", it's still the same concept of FLOW. The haki is flowing outward from Hyogoro in the same way it would when he's putting it into his swords but since there's no sword it just forms a haki barrier in the air. Or it enters something to dismantle it from within. The point is when Armament Haki flows, that's when it's Ryou.
Therefore Ryuo is in fact Advanced Armament Haki since it isn't just basic armament haki. It's flowing armament haki.
And the reason Wano people immediately jump to Advanced haki techniques when learning haki, is because they all need the advanced version to fight. They are all swordsmen. Them learning basic armament is useless so they immediately require knowledge of Ryuo, Flowing Armament haki to put haki in their swords.
This statement isn't true. Mantra is just the Skypiea name of observation haki because there's a panel in the manga saying just that.
On the other hand, the panels supposedly saying Ryuo is just Armament haki is this.
As you can see, Ryuo is Armament Haki focused on FLOW. As in, Just armament haki isn't a thing in Wano. By that I mean there is no name for just armament haki. It becomes Ryuo when the armament haki FLOWS.
This doesn't mean people literally can't use basic armament haki in Wano. They just don't have a name for it. What they actually care about to name is FLOWING armament haki. And why do they do this? Because they are all Swordsmen.
Armament haki is used for fighting. And everybody in Wano fights with swords. Even Kawamatsu who is introduced as a sumo wrestler still fights with swords. Therefore, by default, armament haki MUST be used on swords for Wano people to be useful in combat.
And making your Armament Haki FLOW into your sword is Ryuo.
So basically, Luffy having basic armament haki isn't a concept people in Wano have a name for since nobody fights without weapons in Wano. Hell in Ringo, people are literally given swords at birth just to emphasise how much everybody is a swordsman. Of course even Wano people need to know basic armament first before they can make it FLOW but since nobody uses basic armament in combat, there's no name for it. When the Haki can FLOW into your sword, then it can be used in combat and so then it becomes Ryou.
Even when Hyogoro beats Alpacaman unarmed using "barrier haki", it's still the same concept of FLOW. The haki is flowing outward from Hyogoro in the same way it would when he's putting it into his swords but since there's no sword it just forms a haki barrier in the air. Or it enters something to dismantle it from within. The point is when Armament Haki flows, that's when it's Ryou.
Therefore Ryuo is in fact Advanced Armament Haki since it isn't just basic armament haki. It's flowing armament haki.
And the reason Wano people immediately jump to Advanced haki techniques when learning haki, is because they all need the advanced version to fight. They are all swordsmen. Them learning basic armament is useless so they immediately require knowledge of Ryuo, Flowing Armament haki to put haki in their swords.