Why exactly are you so convinced Russian leadership wants to massacre Ukraine and have a wasteland on the border? Ukraine was a vital trading partner for Russia prior to the western coup. Why do you think that the US and its allies fund a proxy war on Ukrainian territory? Out of the goodness of their hearts? They have been privatizing state assets in Ukraine, speculating on them, taking advantage of the spike in European requirement for US natural gas to replace Russia, and making huge military industrial purchases to replace what Russia destroys.

I'm sure Russia will settle for a slowly steamrolled Ukraine as a second option if the terror attacks on Russian office buildings etcetera continue, they might not even stop at western Ukraine, it could go on for years. They have been willing at many points to freeze the conflict so that they can go on making some money with Ukraine. Like I said it took them ten years to come to the aid of Donbas while civilians were being bombed there (Ukrainian leadership openly bragged about making the eastern Ukrainians' children stay in bomb shelters rather than school). The west chose the drawn out destruction of cities, the destruction of a dam for no good reason.