[Ukraine just needs to surrender. Best for its people. They are getting stomped and the longer it goes, the more the west wants to intervene, then it goes nuclear. Nobody wants nuclear war.]
https://military-history.fandom.com/wiki/World_War_II_casualties_of_the_Soviet_Union
The question is whether Russia can take that level of pain.
Truman threatened nukes over Korea. Eisenhower threatened nukes over Quemoy and Matsu. Threatening and doing are different things. Putin uses nukes, and the Russian population is a literal grease stain on China’s newest western province. Putin goes from maybe Vladimir the Greater to “what is Vladimir?” and “what is Russia?”.
Putin’s not suicidal, and he’s certainly not interested in wiping out the Putin name or Russia as a biological or geographical entity. He’ll withdraw the troops to Russia and set about the grim task of killing his internal rivals once he judges the war to be unwinnable at an acceptable cost.
One thing I learned in Bosnia, when a slav speaks, listen.