I think Zoro is landing the final blow and killing Kaido. That should clear up the huge difference between Zoro and Sanji.
Killer should have a higher bounty than Sanji imo, if we're looking at the how the Kidd Pirates and Straw Hat Pirates parallel to some degree. And I also think Kidd is going to be one of the "Yonko" post-Wano. Maybe not an official "Yonko" title but he will be one of the 4 strongest pirates living. Both Kaido and Big Mom are going down in Wano.
the final blow will be always Luffy's that is how it was always too. and Zoro will have much to do with some one like King.
and Killer has a bounty of 200 mil right now , Sanji and Zoro have now about the same bounty , and it was intended that way Oda telling us they are still rivals and to be honest King and Queen are without a doubt are there just to be Zoro and Sanji's opponents.
and really there is not really a parallel between them anymore
Luffy has 3x Kid's bounty , Luffy has advanced haki , has too many allies . let us be honest here no matter how you look at it they are not on the same level anymore and in Sabaody Sanji , Luffy and Zoro and maybe even Robin all of them could have had 100 mil + bounty if the WG didn't cover up Moria's defeat.
it is amazing how people are trying to make a difference between Sanji and Zoro , sure Zoro has more brute strength but Sanji can compensate for that with speed and better reaction thanks to his superior observation haki .
Oda went all out to make this three stand out. and even in this arc showed Sanji and Zoro rivalry and bickering on each other , they made about the same deeds .
both of them defeated some of Kyoshiros subordinates
Sanji defeated Page one
Zoro defeated
Killer
both of them stepped in to protect O-toko
and Sanji was seen to mock Zoro about his bounty.
if i have to assume that Zoro will make more than defeating King then he will kill Orochi in that case Sanji will most likely rescue Hiyori since i think she will be taken hostage this time.