Sanji vs King has become less and less plausible.
I'm banking on Zoro and Sanji vs Queen together, and Marco vs King,
then later Zoro (with others) vs Kaido and Sanji vs King (weakened).
Here's what I see happening. Marco will be slightly drained due to healing the alliance and will lose to King in a high diff. Once Zoro and Sanji finish up with Queen, Zoro will go on to join the fight with Kaido, while Sanji will finish Marco's work and take down King for good.