"Full potential non-nerfed Sanji" this is an extremely long winded way of saying powered-up Sanji lol.
Sanji says he will get stronger. Sanji is literally saying he will power-up now that he loves himself. He is saying he will change his fighting style.
Did Sanji love himself at the start of Elbaf, yes or no?
So if Zoro and Sanji fought at the start of Elbaf, who would win? Ah yes, Zoro would stomp.
At what point would Sanji give Zoro a good fight in the actual manga? Not at the start of Elbaf that's for sure. Maybe after the current chapter? Oops wrong again, as Zoro has already powered up. So when? Perhaps after he awakens CoC. Has he awakened CoC yet? No. So at every point in Elbaf so far, Sanji has been massively weaker than Zoro.
Instead of waiting 2 weeks for Sanji to awaken CoC and compare apples to apples,you Sanji fans would rather mix and match different versions of the characters that never existed at the same time lmao.