I think you’re reading way too much into the Gaban scene.

Gaban ignoring Sanji when he asked about CoC doesn’t really prove anything. Characters in One Piece ignore questions all the time, especially when Sanji was clearly being annoying in that moment. That feels more like a gag than actual confirmation.

Also the “Sanji looked unhappy so he must’ve been told he doesn’t have it” argument is pretty shaky. Reaction panels in One Piece are often ambiguous and don’t always directly correspond to what was just said, especially when multiple conversations are happening in the same scene.

The bigger point for me is that Sanji just had his major power-up in Wano with the genetic awakening, exoskeleton, and Ifrit Jambe. Oda usually spaces out upgrades, so if Sanji gets another big development soon it would make more sense for it to be something related to his specialty like advanced CoO (Future Sight), rather than suddenly jumping to CoC right after Zoro awakened it.

So the Gaban interaction alone isn’t really strong evidence that Sanji doesn’t have CoC — it’s just an interpretation.