Sanji is > the Rocks crews YCs. Oda never created a YC# tier system (that was made up by the fandom), Oda created a power tier system based on bounties. Those > 1 billion and those not. (Every time the strongest YCs talked about how strong they are itโs always related to their bounty and their hax abilities)
King Queen Marco Katakuri and Jozu are all on the same tier of power. And Sanjis much stronger than Queen hence heโs much stronger than everyone in Queens tier. The closest fight would be Sanji vs King due to match up