Yeah I think the same think applies to black and brown. I wouldn't consider a black African as the same race as an Australian Aboriginal. They have distinct cultures and physical characteristics.

The "woke" kids will say black people in America adopted a culture after losing theirs so they want to consider them a single race but white people can't say they are a single race because they didn't have their European culture taken away. I don't know about that argument, it's not really one I subscribe to for the same reason, it lacks nuance.

Point being dictionary definitions for race are ambiguous, and the idea of race varies for different cultures and parts of the world. So it really does get hairy when trying to talk about American race relations when people try to use nuance in culture for people with one skin tone but also use skin tone to quantify the other race entirely.