So some or even many people explain America’s success as a result of diversity. If that’s true then either China will need to import a diverse population (axis of diversity is uncertain), or else diversity is irrelevant and they will succeed as a more or less undiverse population (whether people are actually Han doesn’t matter so long as they believe and the government classifies them as Han). It’ll be interesting to see.

Diversity is just short hand for US needs to brain drain from around the world, the success is system that disproportionaly increase size of US skilled workforce vs rest, so people better play nice with each other (worked well until not). When PRC went from making 1% of of global technical talent to 50%, and able to retain them or in this case redrain them, they win talent game for generations (at least until 2070s). They will output more stem in next 20 years than US will increase population, births + immigration, i.e. their technical workforce will be 2-3x US. "Diversity" can't brain drain enough to make a dent on those ratios.

"diversity" is an overbroad concept that covers many disparate social practices, a lot of which have nothing to do with technological progress.

I guess that the more focused question is whether China needs to import some amount of tech talent to succeed, at least temporarily. The reporting on this EUV prototype does suggest that that is what they did, giving foreign researchers special visas and whatnot.