Not really. The entire Tibet Autonomous Region has less than 4 million people living in it. Xinjiang is 26 million which is of course a lot but still insignificant compared to China's total population (and almost half the people living there are ethnically Chinese anyway).

Those regions might be politically important to China but demographically and economically (besides any potential natural resources) they hardly matter.

Han make up 91% of the population of China, in the USSR Russians were barely above 50%.

I mean China is a nation state that engages in some imperialism. The USSR was an empire first and foremost.