As adults, however, it is up to them to find ways to deal with their trauma to limit the effects it has on others. That is in no way unreasonable. You cannot, as an adult, expect others to consider your needs above their own.
It’s not like OP hasn’t attempted to address her trauma though. She has, with years of therapy. To what degree it’s been dealt with we don’t know, as we don’t know the impact it’s had on her daughter through her life. It’s entirely possible OP copes just fine as long as she’s not confronted by the biggest trigger of her trauma. Sometimes that’s the best you’re going to do, in terms of ‘dealing with it’. Some wounds don’t heal in their entirety, no matter the treatment.
I do think it’s weird that you would choose to go down a path that you know is going to have these ramifications on people (her mother AND her children) you have a good relationship with.
As OP needs to take responsibility for her choices, so does the daughter.
As a sort of aside I do think this idea that you only cope with trauma if you confront it head on and ‘embrace’ it is dangerous, tbh. That isn’t to say that packing it away and never talking about it is better, but the point is that when it comes to individuals what may work for one can be devastating to another. One person will need to confront their trauma, another may only ever be able to live with it by packing it away. When it comes to human beings there’s rarely ever a one size fits all solution to every issue, and to think there is, is naive at best.
I’m not going to call the daughter a psychopath because I don’t know her. Similarly I’m not going to call her kind hearted or altruistic either. There’s clearly a lot to unpack here, considering context. We don’t know her motivation, and ludicrous or not spite can indeed be a motivating factor that drives people to great lengths.