Tbf having knowledge of an ability is different than using it. Like Zoro and Sanji both learned of conquerors haki during the timeskip
As for him being told he has it in Wano
Brook asked if he used it but he obviously didn’t it was just Kaido moving onigashima
Kaido implied that Zoro used conquerors to scar him but idk and I don’t care to argue tbh
As for king of hell all he was doing was letting enma exude as much haki as it wants. So him not realizing he was releasing conquerors too is fair enough
Him not noticing the people behind him is stupid but fair too I guess
Him not understanding why king asked him that question even more stupid of Zoro but it’s Zoro and he’s pretty damn slow
All I know Zoro not thinking he was a conqueror is another Mihawk downscale