It's quite comforting knowing that zoro is stronger than top 4 scabbards combined, and all of that without ryou.
Also ACoC does not deal internal destruction otherwise ulti's head should be marshmallow after yamato TB but it didn't.
For now ACoC is about the level of tatsumaki, a recoverable cut that made kaido cough blood.
We all know that zoro specializes in CoA, so it makes sense that his armament is stronger or as strong as ACoC.
Some dumb individuals would argue that asura is weaker than ACoC because it didn't knock kaido down, well even pre-udon luffy gear 4 could do it and we saw how unaffective it was. Also we had top 4 scabbards combined attack that made kaido faint for a moment but kaido himself said it's shallow and weak to even reopen his old scar, yet on the other hand kaido said that asura is powerful enough to make a permanent scar.
Everyone is scared of zoro, because when he learns advanced haki, he will automatically stand out as the strongest fighter in the alliance, even oda realized that and give zoro a sword that literally nobody in wano can use without suffering severe consequences, which is by the way the worst plot device in the series.
Ans let's not forget, not even 2 yonko combined can oneshot zoro.