There is no correlation between those situations, Zoro has yet to damage Kaido and a 1 vs 1 is completely different from partecipating to a 5 vs 2 (that most likely is going to become a 5+ vs 1 nerfed emperor)
The end of Wano will signify the start of the endgame, where Zoro should only have difficulty against fellow SN, YC1 and above characters.