The Soviets were pretty brutal, though I do imagine the Chinese could and would go further in that regard. But in the end it would suck the life out of the Chinese just as it did the Soviets. And I imagine the US would do the same thing it did when the Soviets were there - supply the Afgans, including the Taliban, with state of the art hardware. The Russians took a serious beating from the stinger missiles we supplied them.
It’s well nigh impossible to really conquer a country like that over the longer haul.
The Chinese would never actually go to war because their whole society is predicated on the only sons supporting their parents, wives and children. Without that support, the whole society would begin to collapse as there are no western style safety nets.
The deaths of any significant number of men (sons) in a war would be tantamount to signing death warrants for CCP rulers who know this salient fact.