I have not had the cervical medial branch block, so am of no help there. Like you, I am not one of the fortunate who responds to occipital nerve blocks. Tried them over 3 years with 3 different people performing them--they just trigger really bad migraines for me.
I hear you on the difficulty of finding doctors who listen. I've had quite a few over the course of this. Sometimes I feel like each doctor has their "preferred method of treating migraine" and that's it. Doctor one I went to prescribed preventatives and supplements. When my migraine was too freaky for her, she passed me off to doctor two only believed in nerve blocks. Literally, when I sat in his waiting room, he recommended nerve blocks to every patient. When they weren't working for me and we asked if he did anything else, there were no other options. Which was a shame, because otherwise, we liked the doctor. Doctor 3 does botox and now Aimovig. She's somewhat more flexible on prescribing preventatives than the first two, but we still have to go to Doctor 4 and 5 to get orders for my co-morbid condition.
So to some extent, I've had to shop around, make myself into the guinea pig, see what I responded to, and stick with who was willing to prescribe it.