Sanji would only slow Zoro down if he's weakened to the point that he needs protection from Zoro. That's what Zoro is meant by "Are you gonna slow me down?" He's basically asking if he'll have to fight King while protecting Sanji.
King attacked Sanji who's not fighting anyone while Queen attacked Zoro who's already blocking King. If you notice it. Sanji noticed King's attack only after Zoro blocked it while Zoro noticed Queen's attack even before Sanji deflected it. Don't see how this even helps you prove they're close. This is no different from Luffy, Law, and Kid attacking ship to mock each other.
I dunno how to explain It to you, since you don't give any importance to portray.
For me Zoro and Sanji fighting two guys who are both calamities shoulder to shoulder, while supporting Luffy and being called "wings" and "stars" and Oda still portraying them as the two top men of Luffy Is enough of an evidence for me.
But you and the others are obsessed with feats and you are obsessed with what It Is shown that you can't even read through the manga, you're lucky that Oda off-screened everything or you would have seen Sanji vs King and Queen together and not just the implication that It happened, Oda is trying to tell you all that Sanji and Zoro are fighting on an equal foot, but you lack any intuitions skills and just like children you must see It for believe it even though it's already clear, anime will most likely show more of Sanji vs Queen and Zoro vs King, but of course you'll ignore the anime here but you all are gonna consider It for rooftop or any other Zoro wank stuff, I can already see people using anime for saying hakai was more than 1 sec and then say the anime Is not canon when Sanji shows more against King and Queen lmao.