Attacked kaido twice... kaido only notices Enma
When the others attacked... kaido praises their efforts
Zoro the only one relevant because of a magic sword since he had no personal beef with kaido
Luffy, Kidd and Killer lost to Kaido...
Law ruined his plan
Zoro? Oda had to force him there by handing him Enma.
This is why the other SNs are hyped because they are skilled, they fought kaido before and elected how to counter his dura. Law had intels on kaido.
Zoro only there coz the sword allows him to be noticed by Kaido.