I hear you. I have (and still do) experience doubt in myself, because I perceived that the pain/dysphoria I experienced was much less than my trans and nb peers. I also like my singing voice, but hate my speaking voice. I thought for years that I couldn't be trans, because I didn't despise my body, instead I just didn't care about it. I learned that it was a common sentiment.

Until I have another gender crisis, my gender is nonbinary and fluctuates around male and masculine genders (genderfaun is the term that most accurately describes it for me). I found that I could dispel doubt by focusing on all the parts of my gender and presentation that I really love rather than highlighting the dysphoria I don't have.

I can't tell you if you're FTM or nonbinary or genderfluid or whatnot, because there's no one way to be trans. It's a matter of being what feels most like you, and you're under no obligation to find a perfect label if you don't want to. In the end, I think it's about being happy with yourself. Good luck, my friend and godspeed!