There's no such thing as a racial marker - race is completely arbitrary. That's why you occasionally get cases of people pretending to be black, because "being black" is a fluid category and as such people who are white fakers can look very similar to people who are black but light-skinned.
A good example of this is the difference between racial categories in the US and those in South Africa, as
exemplified in the opening scene of Gandhi (1982). In the US, anybody with recent black ancestors can claim to be black, with various degrees of force on the "can" depending on what year you're looking at. Conversely, in South Africa you have a situation where not only does it not match this US definition, but black and white people in SA also have different perspectives - SA has the category of "coloured" for people with both white and black ancestors, with only people without recent white ancestors being "black". And also on the train you see the racists going back and forth calling
Gandhi either black or colored because he doesn't quite fit in the SA racial order at all (my understanding is that this eventually lead apartheid SA to separately define the races as white, black, coloured, and Indian - just those, no other categories).
You might also look at the outdated US racial category of "yellow", not for Asian people but for black people so light skinned they could sometimes pass as white and avoid certain legal restrictions (this term is offensive if extremely archaic now, so don't use it).
People don't know they're black, white, or anything else until they get socialized as such - they know people have different appearances, but as per above people with different appearances can get lumped into the same racial category.
In other words, race isn't "internal", we've just got societies full of racists reinforcing it and so it's hard to escape even if you want to, where as if you try to uproot a person's gender be they trans or cis they'll be horribly traumatized - it's a part of their actual self and existence.
Also, trans and enby people are ingrained throughout all of human history, where as race as a distinct idea was gradually invented starting around the late 1600s taking their first step into ideas of biology.