I can not speak for e everyone, but our situation with Kay is different. She knows we love her and how much we do. When we send her reminders that we love her, she seems even more hateful and demanding of us. I don't think, at least in our case, that Kay acts out because she is afraid we don't love her or that we will abandon her. Her anger is not about our love, although she will use that line of illogic. To her that is her way of manipulating us into buying her things. It worked well for her in the past. She used being adopted too.
And yet, yes, we would cry and send her the equivalent of $400 for that motel room that she did not appreciate. In the past. Not long ago.
Once we finally told her that we will always love her, but that we can't give her money anymore, she cut us off with a long-winded text about how we never loved her etc. So we haven't heard from her in a while. A few relatives she hasnt blocked from her FB account keep us up to date. We are being villified there, but no surprise. Hurtful, yes. At least she is not homeless. Not yet.
The time away from Kay has been mostly peaceful and almost a relief. That triggers my guilt, but it's true.
In my present state, I would probably ghost her too, if she treated me that way. Of course, I can't because she ghosted me first! It is what it is.