zoro usually gets a small win before getting a big win
sanji has to get an L or multiple before he gets a big win that is still smaller than zoro's big win
Oda sure has a favorite lol
To the surprise of no one
Well actually I'd say it's more of a tradeoff
Sanji gets the lion's share of the character moments between them (see: Zoro fans justifiably complaining about being hoodwinked into believing Wano would be Zoro's arc)
But when it comes to shine in combat it also isn't particularly close between them. Wano is actually a perfect example for this
Zoro goes to the rooftop -> puts up MVP numbers against Kaido -> in stasis for a bit -> fights and defeats King
Sanji gets captured by Black Maria -> saved by Robin -> helps on the live floor for a bit -> fights and defeats Queen
When it comes to how they're treated in strictly combat scenarios Zoro fans only get humbled because they have exceedingly high expectations when it comes to pretty much everything. If not for that they'd have pretty much nothing to complain about (again, combat wise... a lot of things regarding his character were left untouched in Wano because Oda took LSD while writing the ending of it)