New to Therapy and Undiagnosed System

Sounds like this therapist isn't a good fit. If you want help with your system you will have to find someone else. Therapists who are quick to discount a system's experiences are not likely to change unless given substantial evidence, to which that is not your job to do. I would suggest looking for a trauma specialist or a therapy practice that works with trauma patients. Since DID is a trauma disorder, trauma specialists are usually pretty knowledgeable or are at least very open to the idea of systems.

I should also clarify, I didn't click with the other doctors for a lot of reasons. But not believing in a disorder is a BIG REASON

That doesn't sound like the right therapist for you. It took me about 3 doctors to find the one that accepted my disorder. There are a lot of doctors who are skeptical, despite the newer evidence supporting systems (read: No Bad Parts, or the Trauma Keeps The Score). It may be doctor shopping, but it literally is about finding your values. A Christian person who wants to stay in their faith will look for a doctor who is Christian as well. You need to get support in a way that's productive for you! As for being trans (I am a trans system as well!) It can be detrimental to mention to your gender therapist that you're a system. It's better to have an endocrinologist AND a therapist, and to keep those fields separate. Otherwise it can get way more complicated than it should be

Unfortunately in my experience, many therapists immediately discount reports of systems in trans individuals as part of the transition. But we’re here to help!!

hey me too!