It’s a not a trivial question to get an answer for by googling.

I literally googled "ethnic groups in china wikipedia" and "ethnic groups in the US wikipedia" and the results (https://en.wikipedia.org/wiki/List_of_ethnic_groups_in_China & https://en.wikipedia.org/wiki/Race_and_ethnicity_in_the_United_States) seem to immediately and unambiguously reject the idea of China as some kind of homogenous ethnostate that the US can't emulate because it has too high a concentration of melanin or whatever fascist bullshit you were trying to say.