Oh missed this in the earlier reply. You can look at it this way, India is losing 8/10 of its top STEM talent but China is loosing 30/100. That means America is getting more top tier STEM talents from China than India.
In percentage wise India looks bigger because they're producing fewer to begin with.
China also has an overproduction of semi qualified personnel, to the point where youth unemployment is fairly high even with a lot of expatriates.
The situation is really not comparable at all. China has about as much population as all of Europe, and as of 2023, the newest generation now has the same gdp per capita as Europe as well. However, the ones going out now are the young adults, which are slightly less affluent.
Still, that means China makes a ton of "skilled" workers (at least on paper skilled lol). Just like you find Europeans pretty much anywhere, it is now also become common that to find Chinese anywhere, as they can afford to move.
In contrast, India still needs every single one of its professionals for development, but it isn't getting them due to cultural/economic reasons.
With a fulfilled demand at home, there's no way China can realistically hold onto all it's population. The best China can do is to sharply discourage expats from going to enemy countries, but the CPC itself is reluctant to draw clear lines between allies and enemies. Raising immigration to for example Russia or certain states in West Europe and Africa/Middle East would be a better solution. From there on, immigrant communities can act as liaisons that exchange Chinese culture to the locals.