Guys you need to get this straight, there are a lot of YC level characters in the alliance:
Luffy YC1+
Marco YC1
Kid YC2
Law YC3
Ashura Doji YC2
Denjiro YC2
Neko YC3
Inu YC3
Jinbe YC3
It's quite clear that characters in Wano arc will be defeated multiple times and will get back even stronger, and that includes both antagonists and protagonists with exception of Yonko of course.
Yes, Zoro and Sanji will get their 1v1 against the allstars in lost round of the war, but as of right now they are not ready to do that, they need power ups and experience, Zoro and Sanji's gole in this arc is to move from vet level to YC1 which is a Big power jump and requires consistent progression in power but before that some needs to fight against guys like:
Smoothie
Snack
King
Queen
Jack
(Possibly Katakuri and Cracker too if they come to Wano)
It's crystal clear that the scabbards are getting their revanche much against allstars since beast pirates used derty tricks against them 20 years ago and Neko and will fight against Jack for sure.
Asura vs King
Denjiro vs Queen
Neko and Inu vs Jack
Asura, Denjiro and Neko, Inu will get defeated which will hype the beast pirates up but then we will have
Marco vs King
Luffy vs Jack
Kid vs Queen
Law vs Smoothie
And in this case the good guys will win but then the best pairets will come back even stronger and at that point Zoro and Sanji will be ready to fight against them.