I see transracial and transgender as exactly the same issue of dysmorphia. Your biology not matching the social role you want to play in our society. Sad that you would need to lie or have surgery because societal conditioning is so strong.
In actual fact it should be even clearer that transgender is not biologically driven than transracial as sex is binary whereas race is not. You can be mixed race but not mixed sex (barring very rare intersex conditions).
There are some biological differences between races on a spectrum eg proportions of slow vs fast twitch muscle fibres that make black people better sprinters. These do not define black and white in a unitary way though like having ovaries or having testes.
I can believe that there is some subtle variance in testosterone levels within men and women on a spectrum in a similar way but it does not define being male or being female that is a chromosome determined binary thing.
You can't say that having a slightly lower testosterone level is a biological driver of 'feeling like a woman' unless having more melatonin or more fast twitch muscle fibres is a driver to 'feel black'.
I recall there was a lot of debate when Barack Obama became the first black president because technically he is mixed race. He is usually defined by himself and others as black but genetically he is as white as he is black. The argument came down to the fact that he defines himself as black and has been treated by society as black so that is his lived experience. It goes to show that race is a social construct if it turns out to be about self definition and experience. I don't condone Rachel Dolzeal's lies but how black would she have to be for it be Ok to claim it? If she had one black grandparent would that have been better?
Similarly I read an interview with Antonio Banderas about how he argued with a US border guard as being Spanish he had ticked a white European box on a form but in the US he was Hispanic which is a racial subgroup we hardly even recognise in Europe. Someone else was trying to define his ethnicity for him and it changed as he moved around the world. That has to be the very definition of a social construct.
Sex is a binary biological reality
Skin colour is a biological reality but a spectrum one
Gender and race are both social constructs
We should be fighting for people not to be defined by their race or gender and to have equal possibilities
We should have sympathy for those who are suffering or discriminated against because they don't fit the societal norm but we don't have to believe in female brains or being born in the wrong body to do that.