What a thorough telling of your own evolution — and I’m thinking your child may be old enough to share the story with you and fill in their version- it might be illuminating!
At 68 I finally came to the conclusion that I am a mirl- a male girl — and no longer felt the long lost hidden persona in me was female. I find I can feel perfectly feminine, at ease with all that defines a girl, while accepting as good all that comes for me as also being male. The closest analogue for me is a tomboy- approaching the same state from the female side. I mention this for your practical catalogue of options for your child.
To put it another way- perhaps to ask them- “Do you feel uncomfortable with being male, or do you feel others are uncomfortable with you being male and free?