AdvCoC strong enough to split the sky only 3 people on Wano are able to do and the other 2 are potentially top 5 characters.
AdvCoO can see into the future a feat no other SH can do.
AdvCoA (internal destruction) at a level he shits on Zolo's supposedly more proficient haki
Devil fruit potentially about to awaken and make him even more OP or Gear 5 which will make Luffy go from mid diffing Zolo to low diffing
Zolo's best feat surviving an attack and beating King (barely) before fainting. So imagine downplaying Luffy for if he gets beat by Kaido again despite the fact Luffy WILL beat Kaido a matter of when not if.
I'd hide under my rock if I was a Zoro stan.