From a (Greek) mythological point of view Hera is the mother of galaxies. Or at least our Galaxy.From a science and language point of view:
Mother of all galaxies would be either “gravity” or “big bang”
Mother of galaxies (of which Milky way is one) could be Sagittarius A*, since Milky Way also has satellite galaxies, or again could be gravity, or big bang.
Mother of Milky Way could be Sag A*, gravity, big bang, Gaia or other mythological goddesses.
Don’t see how this helps
Need more breakfast coffee!
No sure how this helps either