You can cross the straight in from France or take a thirty minute flight from Spain and be counted as “non-local”. Meanwhile, traveling from Shenyang to Shenzhen means nothing.
The islanders of Hainan are no different than the mountain men of Inner Mongolia.
Lol you brought EU into the conversation but didn’t state the statistics for them. The large majority of Immigrants to an EU member state are classified as “Non-EU Nationals” meaning they come from outside of the EU. About 5.3% of all EU population are first generation Non-EU immigrants.
TBH I can’t even tell you what the race, ethnicity, and heritage stats are for the EU because they’ve got the worst demographics tracking imaginable.