AP Scaling:
Zoro scales ≥ to Fujitora who scales to 420 megatons. Can one-shot those who scale above Gear Second Luffy (downscaling from 420 megatons) & can also one-shot Pica who scales to 377 megatons. With amps like Busoshoku, Ni Gorilla and Asura he can enhance his attacking power even further.
Sanji in base downscales from Vergo who scales to Pica at 377 megatons, with Diable Jambe he scales to harming Base Luffy's durability who downscales from 420 megatons. He can further amp himself with Busoshoku.
Speed Scaling:
Both scale to "Possibly Relativistic+" at their fastest so they're both comparable, since diable jambe increases attack speed he would likely be superior in that.
Durability Scaling:
Zoro took Fujitora's gravity and blocked his attack, he also can handle his own AP, thus his durability scales ≥ 420 megatons. Blocking with his swords he would scale to "At least 7-A+" due to his swords durability, with Busoshoku he scales even higher.
Sanji's base durability downscales from Vergo and downscales from his diable jambe AP considering overusing it harms him. His durability scales higher with Busoshoku.
Haki:
Zoro:
Busoshoku: Zoro should be superior in this considering his ability to use koka and imbue it into his blades, he's also capable of overpowering other Koka users with his haki & his armament is likely superior to the scabbards considering his ability to tame Enma. His ability to use "Mighty Blade" swordsmanship also would grant him a lot of superiority.
Kenbunshoku: Zoro is proficient in this regard, definitely inferior to Sanji but not so much so that he gets completely overwhelmed.
Sanji:
Busoshoku: Sanji's Bushoku is pretty basic and only grants enhanced durability.
Kenbunshoku: Sanji is supposedly getting Advanced Observation for his future sight abilities so he's clearly superior.
Overall their both better than the other in their specialty although Sanji is far worse in armament than Zoro is in Kenbunshoku.
Conclusion:
Overall I think Zoro will win this, Sanji does have the advantage of flight & Durability Negation but Zoro can counter this with his ranged slashes and own durability negation. Sanji is still superior in Observation haki but that alone isn't enough to grant him victory.