I'm not wrong though, that is how Shueisha currently officially catalogues the 12 One Piece arcs/sagas.
I mean if you want to call it the Yonko Saga that's fine, but at the end of the day officially it's the WCI Saga and Wano Saga.
Heck the fan term shouldn't even be called Yonko Saga, it's not like Shanks and Blackbeard played major roles, the Kaido and Big Mom saga imo makes more sense.