Zoro and Sanji are mirrors of King and Queen.
King is a defensive juggernaut who outspeeds his opponents and wears them down with fast fire attacks.
Queen is a tactical mastermind who uses tech to enhance his body and alter his biology, with a focus on rotation, who is slower than most, and a master of crushing people with Adv CoA. The only reason Sanji survived this fight is Germa tech, without it, Sanji dies to Queen's Brachio-Hiss. Hell, the only thing that saved Sanji was Queen shooting himself in the ass. Same with Zoro and Enma, without Enma, Zoro loses, he needed the Haki training.
Zoro will focus on Offensive Armament like Queen, while Sanji focus on Defense via Lineage Factor Elements and a unique body, like King.