As someone who has seen a LOT of therapists ... something I wish I had known:
It is totally okay to fire your therapist.

Hell, you may know in the first meeting that you are not "clicking". Ask to be assigned to someone else. Do not spend 18 months with someone you can't relate to and who can't relate to you, spending money, wasting time, spinning your wheels, feeling bad. There is no shame in not clicking with a therapist.
NEVER keep going to a therapist you can't trust. If you are too embarrassed/ashamed, go ahead and ghost them for a different practice or your local neighborhood free health department clinic for a while. Go to student therapists (they're better--more likely to know what trans is and isn't -- they were never trained on that outdated neo-Freudian, we can make our own gender crapola).
In my experience, you will know FOR SURE within 3 visits if a therapist will work out or not. Sometimes jitters during first meeting or your own unhappiness will give you a negative impression or make you feel unsure, so if you're unsure, see if it gets better on further visits. But sometimes you just know right away that a therapist will work or not.
A therapist is like a personal trainer for your brain. If you can't communicate, if the therapist is working in metric and your brain is in English, it's not going to work.
Therapists do not take it personally when clients switch therapists. Sometimes good therapists will even suggest that you move to someone else if they can't help you. Therapy is not a social obligation, it's a way to get better through learning and self-discovery.
As for requiring therapy before HRT, it seems pretty dumb to you and me (btw, I was in therapy for depression and anxiety, which I really, really needed therapy for) but my last therapist (PhD Psychology) explained that there are some rare conditions where a person's identity, including gender identity, will change rapidly. Most providers will want to be assured that your gender identity is persistent and fixed.
My last therapist wrote my letter to the endo. She actually recommended my provider. It's not a big community so the medical folks kind of know each other. We talked a little bit about how I knew I was trans which included some discussion of dysphoria because that's part of my story but she didn't interrogate me to fit some checklist. But I'd already been in therapy with her for some time and she knew my personality and character.