Russia certainly became the greater threat, and perhaps this was spotted in 1944 or earlier. It is possible, maybe, that a peace could have been brokered with Hitler in 1940. It has been indicated in the past that he would have liked to make peace with the Western Allies, although whether this was because he knew he was taking a beating on the Eastern front I don’t know.
The point is however, that the Nazis were a brutal bunch and needed stopping. After 1945, none of the Allies were in much state to carry on against each other. Brutality in Russia however has always been a way of life, but is generally turned in on themselves. Look at the treatment of the Serfs in the 1800s.