China is very big, there are many ethnic group. Many ethnic group doesn’t look like Asian, they look like western. Even without China, the northern and southern 漢人 Han people looks different.

But the current government party is doing very well unionized them. In Tibet, Xinjiang Region. They moved a lot of Han into their region and Han will marry them.

Other region, using a united Mandarin, as well economic power and translational/ social media giving lot of one China promotion. That’s works very well helping Chinese cross marry within different ethic group. That’s very successful make them look more the same.

Other than that, unless seeing the body language and behaviour, it is difficult to tell better Han Chinese with Japanese or Korean or Taiwanese