there is no right and wrong when dealing with trauma. There's simply doing the best you can until you either can do better, or get to a point where survival is no longer the only objective.
I hope the ed treatment helps. I also hope they understand the trauma component to your ed, and can start to help with that. I was lucky when I started ed treatment, they were aware that something else had to be going on. I knew of some of the trauma but had forgotten the rest. They were patient with me anyway...
I've tried dbt a bunch of times, and some of it has stuck with me (I react badly to what comes off as very invalidating when they taught it to me. Though I've heard other really positive experiences with it). If you can try to be gentle with yourself around it, it can be a really good set of skills... abuse has a way of making you think you are **** though, so I can understand the difficulty in being kind to yourself. You *are* clever, but those skills are not helping as much anymore, which is why they are suggesting a change. You did what you needed to in order to make it through. That's ok. It worked at the time.
you are worth fighting for. You deserve the best help you can get. You are clever and very resourceful. And even if you're broken, you're still fighting. That takes incredible strength.