I do agree with this, the only personal-experience thing I want to add is that the “demon” Buné really does seem to be either a mask or, of closely linked to, the goddess Wadjet. However, working with Wadjet directly using her iconography is a good way to avoid any confusion.
But I share the dislike of just assuming all demons are really older gods, and general reductionst concepts that all things are masks of a small number of beings.
At its worst, this concept lays beginners open to parasites who will claim to be the “true” name or form behind a handful of different beings who share certain characteristics, and deceive those people grievously.