The problem the Soviets have with a conventional war against China is that even with their better equipped troops, powerful aviation etc in order to make any advances and contain any counterattacks outside the USSR they are going to need a lot of boots on the ground. As a result they will have to draw from the forces arrayed against NATO and also keeping the lid on in Eastern Europe. Keep it conventional in China at the cost of risking control in Eastern Europe is not something the USSR is going to want to do. The only way the USSR can achieve anything militarily against China without robbing Peter to pay Paul is to use WMD. I doubt the Chinese are well equipped and trained to deal with chemical weapons, and that would be first choice...setting off nukes would be worse, and the fallout would piss off Japan, Korea, and the West Coast of the USA.
IMHO the Soviets might want to actually nip off a few bits for geographic reasons, but actually occupying China?? Insane...defanging it, getting rid of nukes, and installing a friendly communist government if possible, but otherwise nope. Sure there are some empty spots, but the Russians really do not want millions of Han Chinese, or more Muslims to add to their minority issues.
IMHO the Soviets might want to actually nip off a few bits for geographic reasons, but actually occupying China?? Insane...defanging it, getting rid of nukes, and installing a friendly communist government if possible, but otherwise nope. Sure there are some empty spots, but the Russians really do not want millions of Han Chinese, or more Muslims to add to their minority issues.