If Harris was born in the US, moved to Norway when she was 3, went to school in Norway, studied in Norway, then returned to the US, what ethnicity do you think she would identify with?
Identity with, or identify as? You can choose the former to an extent, but the latter is biologically inherited.
Why would you connect such unconnected things as phenotype and heritage?
Fine, since you’re getting hung up on definitions, instead of “phenotype” say “inherited physical characteristics”. I don’t feel like getting into an argument about genetics, it’s beside the point. The point is, people inherit physical characteristics common to their enthnicity, and that is what “race” is. It’s not a bad thing, just a descriptor.
The connection is not “You have black skin, therefore, you are African American”
The connection is “you have black skin, and wiry hair, and African ancestry, and X and Y and Z, therefore you are Black.” And it’s less a connection than a definition. No value judgment, just a statement.
It sounds like what you should be arguing against is “you are Black, therefore you are inferior”. Which would be a really easy and common argument to make without all this bullshit “race is imaginary” crap.