Korea and maybe very specific slivers of the Kazakh border are the only other places along the Russian border where there’s really even any sizable population on either side. in all other places its just people fighting with the trees and general mud / general frost.

If you draw a line from the Caspian sea to Vladivostok, which would basically be the contact line between a Russo-Chinese conflict. the only places immediately in range a for either side that have a lot of people are parts of northeastern China, the city of Vladivostok the Korean Peninsula, and Uzbekistan. everywhere else both sides would logistically starve themselves. cause its just miles of nothing