eclipse,
It’s hard for me to express my sorrow to hear of your difficult situation. But as you know already, you have many people rooting for you.
Let me preface my following remarks by saying that I don’t have much knowledge besides what I have heard in shiurim.
I want to suggest a few ways to get your daughter to connect with you. The first one, which has been mentioned above, I heard in the name of Rav Yehuda Addes. Buy the child little presents to show you care. Do so every day. Although, with a teenager, that may be just a first small step.
I think that with a teenager, who is coming into adulthood, she wants to be respected as an adult. At that rate, ask her for her opinion of things and carry out what she suggests. Set the situation so that the outcome is acceptable to you. For example, go clothes shopping with her and have her pick out something for you. Maybe pick out several garments and let her decide which one you will buy and wear.
Also, try to get interested in the things that she does, which shows interest in her- making her feel loved and respected.
From what you describe, she feels neglected and unloved, so she is looking for love in all the wrong places. She does not trust her parents, nor is she convinced that they love her.
Another thought is that you should have you older daughter try to befriend/mekarev her. She can relate better as she has been there, and your younger daughter may trust her more (or mistrust her less).
I heard a shiur recently from R’ Yaakov Yagen who has dealt with OTD kids. He said that one theme he has seen with OTD kids is that if you ask them when was the last time their father played sports with them or mother played a board game with them (or whatever recreation people do now) the OTD kid will usually say never or I can’t remember.
I know I’m kinda rambling… Hashem Yaazor … May you and your daughter sleep well tonight and every night peacefully at home.