And also, I personally think that vaders redemption at the end of episode 6 was false.
Vader killed billions of people. He destroyed an entire planet for the lulz.
And he was a whiny little shit his entire life before becoming Vader.
One tiny little moment of redemption is not enough to undo all the shit he did.
It is my opinion that the force ghosts shown at the end of episode 6 are being created by Luke Skywalker to assuage his own mental trauma of the series of events that had let him to that point.
He did that so he can tell himself that he is a hero, that he is not a failed Jedi, that all of the pain and suffering he had been through was worth it.
The only reason why Leia could sort of see them was because she was tuned into his force power