CoO is not likely, Oda isn't making Sanji simply win a fight because he dodges good, like he was Katakuri and his opponent was WCI Luffy getting ragdolled. Oda already showed how good Sanji's CoO is when its convenient, similar to how Luffy's Adv CoO only works when its convenient.
Its either CoA (which i think its unlikely, cuz Sanji already has CoA and the Exoskeleton, and his flames are his main source of power) or CoC, that way Oda would create a new Devil Leg version with CoC coating.
Sanji needing to improve his CoA in the middle of the battle wouldn't be enough to increase his flames significantly like did with Ifrit Jambe imo, just in order to beat his next opponent who probably wont even be focused at being tough, like Queen is.
So i think it is going to be CoC, and then CoC coating, otherwise just a new technique Sanji developed offscreen. Actually there could be the case where Zoro and Sanji barely need power ups from now on like they did at Wano, just being more smart and developing new techniques depending on the situation could be enough.
Its either CoA (which i think its unlikely, cuz Sanji already has CoA and the Exoskeleton, and his flames are his main source of power) or CoC, that way Oda would create a new Devil Leg version with CoC coating.
Sanji needing to improve his CoA in the middle of the battle wouldn't be enough to increase his flames significantly like did with Ifrit Jambe imo, just in order to beat his next opponent who probably wont even be focused at being tough, like Queen is.
So i think it is going to be CoC, and then CoC coating, otherwise just a new technique Sanji developed offscreen. Actually there could be the case where Zoro and Sanji barely need power ups from now on like they did at Wano, just being more smart and developing new techniques depending on the situation could be enough.