Sanji vs Kizaru is a fight that many fans hope will happen during Luffy's eventual encounter with the marines. However if you actually look at it, this fight seems really, really unlikely imo. Why?
Well the Luffy vs marines arc isn't as far away as some might think. The events of reverie set up a marine arc happening almost directly after wano kuni. Oda stated that Sabo, hancock, and vivi will be in big trouble in the manga next year, which means that Sabo and Hancock will likely be captured by the marines, with Luffy having to save them.
Hence, I think that Sanji's fight amongst the marines should be someone that he could reasonably beat. I simply don't think that Kizaru is such a person. Maybe if Sanji learned FS, he could keep up with Kizaru's speed but even then, we saw what the admirals could do back in punk hazard. How can sanji, who will be YC2 tier at best post wano, even possibly keep up with such a person? It just doesn't make sense imo.
Its also kind of an awful powerscaling because Luffy, for obvious reasons, will be taking on Akainu in the marine arc. Sanji 1v1ing Kizaru would imply that Sanji is on Luffy's level, however its pretty self evident that this not only isn't the case but never was the case.
Lastly, most of the SH vs marine fights have buildup, imo. Akainu is practically one of Luffy's arch enemies at this point and has been since he put his fist through Ace back in marineford. Zoro clashed with Fujitora several times in Dressrosa. Sanji vs kizaru has no buildup whatsoever apart from the fact that they both use kicks and Sanji needs strong CoO to beat Kizaru, but this was also an argument that was made for Sanji vs Katakuri, and that never happened.
Sanji does have build up for a fight with a marine, however
Drake vs Sanji has had a good amount of build up this arc. Given the Big Mom x Kaido alliance, I'm sure that Drake will choose to ally himself with the SHs for now, however he is still a marine, which means he will be an adversary to Luffy in the arcs to come. I think that the Sanji vs Drake rivalry we saw in wano could be buildup for a bigger fight in arcs to come where Luffy has to take on the marines to save Sabo. Here I see Drake being more than a worthy fight for Sanji and a much better fight for him than Kizaru, who he cannot feasibly beat anytime soon.
Also, I dont think it makes sense for Sanji, or any SH for that matter, to fight a marine in the EoS war. The main antagonist of the EoS war isn't the marines, its IMU and the celestial dragons. Sanji's fight in the EoS War will most probably be a member of the gorosei. Kizaru, imo, will be taken out by blackbeard off-screen during the events of wano kuni.
TLDR; in Luffy's fight against the marines, Sanji will probably fight Drake or an SSG, but definitely not Kizaru, who he cannot conceivably defeat any time soon.