Hiyori says Enma is one of the swords that were capable of scarring Kaido. It's clearly shown that Enma is no regular sword the moment it drains Zoro's haki to the point of physically affecting him. Zoro says he needs to unleash more of Enma's power. Kaido senses Oden in Enma, and Big Mom feels the sword is no common sword.
I'm not denying that Zoro is a relevant part here because he's the holder after all, but whoever denies at this point that what is happening right now has something to do with Enma itself and not Zoro's own strength is delusional. In no way such amount of references to Enma means nothing or can be transferred to Zoro; the emperors aren't minding Zoro nor any of his other swords, they are worried about Enma and Enma alone. And this completely fits the narrative we've been given around this weapon since day one.