Why are poor countries around China worried about illegal immigrants from China?

Hehe, people in China are good at doing business and hardworking now, but the market economy (low-end) in China is almost complete. With the rapid inflation in China, illegal immigrants from China must lead a hard life. In China, a relatively poor country, they have so many years of precedent and experience in starting a business in China, as well as their hard-working and thrifty lifestyle. They can easily succeed and become rich. Then as time goes on, the more wealth is accumulated, and the economy of a poor country is limited. When a large amount of wealth is accumulated in the hands of a few people (China people), will the authorities feel at ease? There is also a plot of China people's hometown. They have transferred a lot of wealth back to China, so they have less wealth (in poor countries). Also, when China is easy to become powerful, how can those illegal immigrants from China still be children of China? Some problems are really difficult to deal with.