As Laurie stated, there is a wide variety of opinions from Doctors, my OBGYN isn't concerned about checking my levels, my GP thinks levels matter and I agree with him, so he does the blood work and let's my OB handle the Estrogen script. It works for me because I live in an area that has no other providers that handle this kind of care, the next nearest is a 6 hour drive.
Keep in mind this isn't a perfected science, even in CIS females levels vary by very wide margins, so it's a bit of knowledge mixed in with a bit of personal opinion.
I do the injections, this was decided on after a in depth discussion with my Dr about my medical history, the pros and cons of each route, as well as each med. I can't stress enough the importance of a nformed discussion based on medical facts not opinions. My advice is to talk to your provider about your concerns, ask questions until you are comfortable with what is being said; that doesn't mean you have to agree 100%, it means you need to understand his position. Advocate for yourself Hun.
Hope this helps. Oh, one other word of advice, patience! This is a life long marathon, take your time and enjoy the journey.
<3