Ugh, it is so very hard to find a t who can work with this. I met with a possible new t two days ago, but when I brought up the topic of dissociative disorders she repeatedly called it 'disassociation'. Which tells me pretty clearly she doesn't know trauma theory as much as her title of 'trauma therapist' implies she does.
I guess I don't understand why more Ts don't understand about this stuff. I struggle to believe that my experience is that 'rare'. Surely there are plenty of other people out there who experienced developmental trauma and have a dissociative disorder as a result?
These days I am pretty much giving myself therapy (I know what needs to be done) and just need someone else to be there to bear witness and to support. But I need someone who can tolerate hearing what I need to share, and knows enough about dissociation and severe trauma to respect my process.

One thing I have learned and am doing differently this time round is to not question anything that comes up. In the end it doesn't matter if what my alters have to share is actually truth or not. It is their perspective, their experience, their reality and what they need to share. This has made all the difference to our progress... things are beginning to heal instead of be stuck in a stalemate of some parts having their reality denied by others. I am finding what matters most is internal connection, compassion and care. Their experience is what it is, and me questioning it, doubting it, disbelieving it doesn't help any of me at all. We will never know the actual truth of what happened, but us doubting and denying ourselves just serves to keep us dissociated and vulnerable. I don't know if it is an option for you to try that or not with your own current situation. But it has definitely helped us a ton.