On this we can definitely agree. I still think Xi isn't much interested in a conventional, shooting war. Anyone with half a brain can see what a waste of resources that is in this day and age.
The only real value in conquering a nation is to get your hands on their resources and recover your costs for the war. Otherwise, you're just blowing up the things of value. The citizens are never going to accept you, so you have to maintain and militarily support a puppet government.
Realistically, what will Putin have, if he succeeds in taking the Donbass? The towns, the factories, and the infrastructure will be bombed back to the stone age, and he'll have to spend a vast amount of money rebuilding before he'll have anything of real value or use. Those citizens they don't bother to kill, will have to be fed, housed and clothed until you can get them to the point where they can contribute to GDP.
Look at how much blood and treasure you waste blowing up and rebuilding Iraq and Afghanistan. What a waste, when you consider the condition your own infrastructure is in.