Op, I am also a survivor of child abuse, I understand how hard it is. It was in no way a criticism of you just an acknowledgement of your position. You have said yourself that you are emotionally distant. It is a way to protect yourself, and is completely understandable after what you have already been through.
You have come from a childhood of abuse, and you find yourself back there again now in a different form, because of a lack of boundaries. I have the same problem. If you did not put boundaries in place that were strong enough when they were younger, in an effort to be the best mother you could be/make up for the shortcomings of the girls father then we can not be surprised that further down the line, both dds overstep the mark in the way they treat you.
This is not your fault, nor theirs actually.
They have been allowed to get away with far too much, and it is going to be harder to put those lines in place now that they are older. I think you need some help with it, proper help so that they listen.
Your dd sounds like a classic case of wishing to be a famous musician, with you facilitating her dream, and then the crushing disappointment of realising she is just average and ordinary like the rest of the world. And in fact even those famous musicians are just average and ordinary. A sense of depression and futility can follow, and should lift when she finds another avenue to enjoy her life, but she needs to do this herself. You can not do it for her.
You have done your best, cut yourself some slack, cut the dds some slack. In the end it can be a hard slog, this thing called life. Send them your love, go on holiday and get some family therapy in place. Sell it to your dds that you wish to listen to their POV with someone there to assist, and ask them to come. You will all benefit from a mediator.