I don’t know that I agree with the idea that the “just Rey” ending would only work in the context of a Rey Palpatine edit. Regardless of what we find her lineage to be, Rey’s arc has always been about self-acceptance and the realization that it doesn’t matter who her parents were: she can forge her own path forward. I think her becoming comfortable with the fact that she’s “just Rey” is equally poignant if her parents are nobodies. “Rey Skywalker” is just her latching on to new parental figures, which I don’t think shows any growth for the character. I do wish there was more in this movie to sell it though, since TLJ does all the heavy lifting.