That would be my guess too. But as I read scientific paper regularly, I can't ignore how vast majority of the author names (well at least in STEM, ML/Robotics,

That would be my guess too. But as I read scientific paper regularly, I can't ignore how vast majority of the author names (well at least in STEM, ML/Robotics, latter is my interest) are Chinese. I don't think those young talents would mind moving to China, especially when anti-asian sentiment have been on the rise since Covid. But since many renown European universities/research center also have those bright young Chinese mind, I guess the Chinese in US can also just move to the more friendly part of Europe (Switzerland etc). There's also HK, where you can get by with English just fine. And they're making new research centers as we speak. (although my HK friends tell me it is getting more Mainland Chinese day by day and expats are leaving).