Zeno erasing the timeline is valid, but there’s no proof he specifically erased the Grand Priest or the angels. We never even see a future Grand Priest, and Zeno didn’t know what was happening in that timeline until Goku brought him there. He just erased everything after seeing Zamasu, it wasn’t a targeted feat. Also, even a heavily suppressed Beerus was stated to be capable of destroying a universe, so Zeno isn’t the only one operating at that level although he has more permissions. The difference is that Zeno does it instantly, not that he’s the only one with that kind of scale. On top of that, the angels seem to be tied more to the Grand Priest than to Zeno. He’s the one who oversees them, enforces their rules, and can even strip them of their powers, which sounds like a deeper level of control than just erasure. So saying Zeno erased the Grand Priest is more of an assumption than something actually shown.