Maybe he does, maybe he doesn't- Oda has never specifically focused on Sanji's CoO to make the point that Sanji's Observation Haki is anything special. If Sanji did or does have some kind of special CoO, then Oda would need to point it out specifically, show it in the manga.
I don't see Sanji's CoO as being a Advanced one.
The 4 basic techniques that one can learn and use after acquiring Observation Haki are:
Presence Sensing- Ussop used this one to locate Sugar
Strength Sensing- Blackbeard used this one to gauge Luffy's strength when they first met in the bar
Emotion Sensing -
This is the one Sanji used to hear and feel the pain of women that was a trap in the Wano Arc
Intent Sensing- this is the normal and most common ability of Observation Haki, used for dodging attacks
Future Sight is the only Advanced technique revealed in the manga thus far, and only Luffy and Katakuri have shown to be able to use it.
Haki/Kenbunshoku Haki | One Piece Wiki | Fandom
I say that Sanji just used the basic Emotion Sensing technique to hear and feel the emotions and voices of the women crying for help (which wasn't even real, it was a trap set up by Black Maria's subordinates).
So no i don't believe that Sanji's CoO is stronger than Luffy's, its the reverse-Luffy's CoO is stronger than Sanji's, since Luffy is the only one in the crew who has shown to be able to use Future Sight, the Advanced technique of CoO.