Sinking, I just want to say welcome, and you’re in the right place. I’ve only been here a few weeks but i have already found a lot of comfort and wisdom here.
This describes my difficult children also, especially at that age. I’m still struggling with them. Once they are adults, we really have no control and it often seems very little influence. I think you are right to not take abuse from her and no time have her in your home if she can’t comply with minimal standards of behavior, respect and responsibility. You do not deserve to live with abuse.
What I am learning here is to focus on what I can control: my responses, my emotions, my boundaries.
Two of mine go through the same cycle you describe of couch surfing or other makeshift arrangements that inevitably fall apart. I just set my homeless son up with the deposit and first months rent on a room only to have him get a 30 day eviction notice 2 weeks after moving in. Not his fault, of course. It never is. Everyone he moves in with just happens to be totally crazy or unreasonable. 
So there’s money down the drain. Again. I was hoping to get him under a roof and set up with a home base where he could get a job and take steps forward before the cold weather hit. Now it looks like he’ll be on the street again in mid October. I can’t have him here, and I can’t come up with another lump sum to get him set up somewhere else.
All this to say - I get it. It’s not easy to know what to do for them when they aren’t helping themselves. I think all we can do sometimes I sleep the door open for when they are ready, and pray that day comes.
Hang in there. Hugs to you.
