Well, in some countries, you now can change your gender and society must acknowledge your transition, use your chosen pronouns, and treat you as the gender you've chosen (male, female, non-binary, genderfluid...) if they don't want to be guilty of a crime.
I suspect soon we'll develop language for transracialism, so you may not be able to change your nationality easily, but your ethnicity will be purely based on identification.
So, if you can move to these countries, you do get to pick and choose how society must address you based on how you see yourself or want to be.