I think that about sums it up. There's probably zero chance that my sister is ever going to admit that she was dishonest in making me out the villian and herself out the victim back when she was acting badly. Short of her doing that, nothing she can say will atone for her being the witch she turned into at that time. If she did it once, she is capable of doing it again. I don't plan on opening myself up to ever getting treated like that again.
Playing the role of "lady bountiful" now gives her some self-satisfaction. She likes making others the beneficiaries of her largess. She puts a lot of effort into cultivating the self-image she wants to have of herself. She does do nice things. She likes to offer her charity to her close relatives. I'm not interested in her handouts. To insult someone repeatedly and then give them expensive presents is crazy. I think, in future, I'll just continue to thank her politely and then move my attention elsewhere.