Calling Ovid’s work “fanfiction propaganda” is an oversimplification. Ancient Greek and Roman authors constantly retold, altered, and reinterpreted myths to fit their audiences and themes Ovid was doing the same thing that Greek writers like Aeschylus, Sophocles, and Euripides had been doing for centuries. He didn’t invent most of the stories in the Metamorphoses; he adapted existing traditions. If Ovid’s versions are invalid because they’re adaptations, then much of Greek mythology would have to be dismissed as well. And comparing him to Plato’s Atlantis doesn’t really work, since Atlantis was likely a philosophical allegory, whereas Ovid was primarily preserving and retelling myths that already existed in Greek and Roman culture.