I'm trans too! FtM.
I never considered my death desire could be tied until recently.
I've bounced key memories off my mom to get a general age when this began and my oldest memory I was two.
In simple terms... I wanted to die. I'd fantasize every night wondering what it would feel like. At first, I just acted things out so I didn't fill in my role in my mind with a specific image. It was me, whatever that meant in terms of appearance.
At six I asked my dad if I could ever be a boy and he said no because god made my soul a girl. I mourned this for a long time, then didn't say anything about it ever again. So in my fantasies I was female because I felt I had no choice.
Skip ahead ten years. Depression flipped my want for death I to a violent suicidal urge. Despite multiple attempts they failed spiraling my depression into a monstrosity.
I find my wife, get out of the toxic environment that was my house, but the depression was in total swing. I tried more times than I can count.
Then I decided to face that I was trans. After 3 years of struggling to come to terms with myself I did and the moment I did my violent suicidal tendencies and my depression ended. But that was when I learned that being suicidal and wanting to die were actually 2 different things. I still want to die. I can't fall asleep without a mental death fantasy (to fall asleep it can't be sexual). I can't orgasm without a death fantasy in my head.
I didn't aspire for anything in my life because I want to die more than anything. If someone walked up and said, "I could give you all the money you need to fully transition or I can kill you, which do you want" I would be torn. Chances are I would settle for death.
But that isn't how life goes so I'm focusing on transition so I can at least have happiness.
I've been lucky enough to marry the perfect wife for me and we have a house and jobs we enjoy. I can't complain about life...I would just rather not be conscious.
I went to therapy and it has been confirmed to not be a form of depression. Something in my head is just a little broken I guess.
I do imagine myself male in my fantasies now.
And I don't get off to violence on females as strongly as I do against males since I do insert myself as the victim.
My therapist and I gave up on finding an origin to my death desire. We concluded knowing the origin was unnecessary. You may never find an origin to yours. If that happens, don't let it bug you.