“Han Chinese” is, at least I think, an idea closer to pan-ethnicity, than it is it’s own ethnicity.
The problem is that there are lots of other ethnicities in China which are not in any way part of that supposed “pan-ethnicity” and pretty much every high-up government official that is in charge of anything outside their own ethnic group is from that “pan-ethnicity.”
As I showed this person I was talking to already, you can make the same argument about Judaism, that it’s a “pan-ethnicity.” There are Ethiopian Jews, there are Yemenite Jews, there are Russian Jews. There are, in fact, even Chinese Jews. That doesn’t make Israel any less of an ethnostate and defending either country’s bigoted practices by couching behind what does or doesn’t count as an ethnicity is really missing the point.