That's Factory Reset Protection. You can turn it off in settings, if you don't want that security feature.
But yes, factory reset on Android phones only wipes the user data partition. Your phone has other things that don't necessarily get reset under a factory reset too, for instance: eSIMs (which is useful that it doesn't, in my experience)
But yes, factory reset on Android phones only wipes the user data partition. Your phone has other things that don't necessarily get reset under a factory reset too, for instance: eSIMs (which is useful that it doesn't, in my experience)