The ways it looks right now, we have Who's Who who is busy with Jinbei, Sasaki who is busy with Franky, Ulti / Pageone who are busy with Usopp / Nami, Black Maria who is now busy with Robin / Brook. Apoo is screwed, and Hawkins is probably planning to switch sides, so which only leaves a calamity as a potential fight for Sanji
However, Oda put King away from the killing scabbards plot by using him being occupied(most likely by Marco) and thus sending someone else in his stead. Furthermore, there is a greater thematic between Marco and King, both being the strongest in their respective yonko crew, both being flying zoans, both having parallel in the way a yonko wanted to recruit them, or the way they sent the Big Mom pirates flying, with King representing the subordinate who believed in the old generation power while Marco representing the one willing to trust the power of the new generation, and thus it thematically leading to Marco potentially ending up proving himself right
One could think the setup is for the battle with Jack who is heading to kill the scabbards that Sanji doesn't want(worried about Kinemon), but Momonosuke also needs to have an interaction with the scabbards(and Hiyori as well for the matter), so with Yamato acting as his bodyguard, she might end up meeting whoever will aim at finishing the scabbards, in this case being Jack
On the other hand, there is much more build-up between Sanji and Queen. Queen is the one who sent the tobi roppo to beat Sanji(O Soba mask), Queen is also the one who was interested in Sanji being Judge's son while looking at both Zoro and Sanji's bounty posters
And if the shadowly figure really is Hiyori, she would probably have an interaction with Queen who always loved her, with this acting as a setup for the confrontation between Sanji and Queen. Not to mention, Queen loves to experiment new things like he seemingly did with his own body, which could make him interested in the raid suit
The issue however is that Queen(with King) seems to be occupied by Marco right now, since King wanted to go but was occupied(and thus Queen who was alongside him should have gone in his stead if he wasn't), but i doubt it'd happen for long, and there is also Drake to consider since he was someone Queen wanted to kill. So i'd say Sanji's match-up depends on Yamato. She might be the one to fight Jack, in which case, Sanji will fight Queen, otherwise it'd be Jack