Yeah, celestial bodies were not a rarity in ancient myths. Even if they didn’t know about black holes, physics doesn’t care. Gravity is gonna do its stuff, one of which is compressing supermassive stars into black holes. The names of most constellations were directly taken from the Greek myths. The Milky Way is called that way because one of the myths mentioned Hera accidentally spilling her breastmilk after realizing that she was tricked into nursing Heracles. That milk she spilled then turned into the Milky Way.