https://en.wikipedia.org/wiki/Immigration_to_China has a good summary (click through to its sources); as of 2020 there were about 1.5 million immigrants in China, just under 600K of which from Hong Kong/Macao/Taiwan; as of 2023 there's 12.000 people with permanent residency cards, which would be the expats that live and work there without nationalizing.
The relative population size of those countries likely plays a role there. Split China into 4 countries, each with a population about equal to that of the USA, and I bet that number for China goes up significantly. Split it into 75 countries each the size of the Netherlands, and it would go up even further (some people moving home within Beijing would emigrate)
The relative population size of those countries likely plays a role there. Split China into 4 countries, each with a population about equal to that of the USA, and I bet that number for China goes up significantly. Split it into 75 countries each the size of the Netherlands, and it would go up even further (some people moving home within Beijing would emigrate)