There is no scholarly consensus on the origin of the medusa legend, or her backstory. There is no medusa canon. So you shouldn't come in here and act authoritative about it. Just saying.
Ehhh, to nitpick, the part about the backstory is a bit dubious. You're unreservedly right there is no scholarly consensus on the origin of the Medusa myth, or the Gorgon myth, or the 'gorgon' imagery in general; it's unclear what order these developed in, either, if they weren't all together. But Medusa's
backstory though isn't so much a case of no scholarly consensus? It's certainly something where we don't have all the information, not by a long shot, but it's very clear that there were multiple different, mutually exclusive backstories. I think it's fairly safe to say that there are a lot of different versions in different places, at different times, maybe just held by different people.
After all, she can't very well be an ancient sea-monster born from primordial deities, and a human priestess of Minerva who got later monsterified as punishment for hubris/victim-blaming. That last one
is unclear if that goes back beyond Ovid at all, but still, there's (if less dramatic) enough variance that there's definitely no one version of her backstory. So people today can definitely pick a preferred backstory if they want (though I think ignorance of how Ovid's version is not the literal only version is a bit problematically spread).
More to the point though, I think it's clear that the idea of Medusa as one individual, one of three sisters, in one way or another was how it was for a
long time in a
lot of places. (The sisters being named Euryale and Stheno, I'm not sure how common how that was, but certainly less universal.) But we don't know that Medusa started that way. It's entirely possible Medusa started as a single figure,
the gorgon—she was also called Gorgo, after all. And all the later gorgons later derived from her; tripling as goddesses often do, to make her sisters, and the progenitor figures like Gorgon or Aix later justifications for her. But it's equally possible, with how widespread the gorgon imagery as protective symbology across Greece was, that gorgons as a type of creature came before any specific figure did; and the name Medusa could have been applied to them at that point, too. It essentially just means "protector", after all; and gorgon means "dreadful" or "frightening" (though that etymology has some dissenting opinioms, I think?) And there are other options, like there starting with a protypical gorgon who wasn't Medusa, or an earlier thing transforming into the gorgon we recognize, or the like.
So, on the one hand, you'te absolutely right. There is no one answer and we can't be authoritative.
Still, the modern "Medusa" or "gorgon" is absolutely unequivocally based on a fairly late reception of Medusa as a definite single figure among three total gorgons. That's why it's pretty girl with snake hair and no wings or brass hands or actually ugly faces. Because it's based off of that reception, art of Medusa after the Classical period inside and outside of Greece carrying on the character and the stories and the artistic traditions of her depiction, carrying forward the myth of gorgons as real petrifying monsters. Contemporary Medusas in Japanese fiction reflect gorgons and Medusas in contemporary Western fiction, which borrow from mythology but also Medieval and Rennaissance European depictions, that one weird bestiary is why D&D's gorgons are metal bull-things, and obviously modern takes on gorgons in Japan or other places reflect back and it's just a whole messy web and kind of gorgeous. Sorry! Got carried away there! I also wouldn't be surprised if Medusa had ongoing reception in some places in Asia and Africa following the Hellenistic period, this is by no means a straight line, but that I don't know if we know much of offhand.
So in that respect I guess it really just underlines how this is a constant tradition whose start is beyond our sight and viewing it as having a defined start in mythology as a perfect, well-defined, clear picture that we can deviate from is flawed.
But, still, for almost all the chain we can still see, up until fairly recently, Medusa was an individual, not a species. So like. It's kinda a bit much to say people rankled by that are wrong just because
maybe that wasn't true of an earlier stage of the myth that we just don't have anymore and likely never will get? While fascinating and worth talking about I don't think
that level of deference to uncertainty in mythology is really called for in this sorta situation.
Anywhosie I want to say that the tradition of "You know the monstrous woman so hideous she kills you if you look at her? Let's depict her pretty." goes back to at least the 400s BC, both in art and writing. Don't ever let
anybody tell you cute or hot gorgons are a modern affectation, this shit goes back to Ancient Greece. There have
always been people who knew the true appeal of monstergirls. (And of monsterboys, too.) And amen to that.