The Chosen One thing is something is wish George never explicitly answered.
He said Anakin was the Chosen One, and if you only look at Lucas’s films that makes sense.
It’s more just a PT thing, I find. I guess it does work in all movies if killing the Emperor was all he needed to do, it could work. However, the OT never really says much about old Anakin beyond “good pilot,” “good friend,” and “good at being a warrior.” He’s decidedly not a chosen one there.
The Paul Atreides comparison, of Anakin being a false messiah (committing atrocities through their power, generated from their charisma and natural warrior skills), can kind of fit within the PT and OT. I kind of prefer this interpretation, of a false messiah turning into a proper one once all was said and done.
If one views Luke or Rey as the extension of Anakin’s deeds, then he could still be a proper chosen one. Also, nothing about the prophecy says that balance had to be permanent.
But the only thing Anakin did to fulfill that role was kill the Emperor, and since TROS revealed that he did not actually kill the Emperor, he can’t be the Chosen One. It must be Rey.
This is why I like the ghosts at the end of Ascendant (Palpatine and Nobody versions) - Anakin still helps finish the job and it would have been impossible without his deeds in life.