1. The USA fought from Normandy and Southern France into Germany. That is not across most of Europe. If anything, the Russians fought the greatest land distances in the war. You said we fought almost all of Europe, that's a subtle distinction.
2. Appeasement happened in the Spanish Civil War, Seizure of Austria and destruction of Czechoslovakia. France and the UK did nothing in those crisis to deter Hitler. The USA had no troops in Europe, nor the available troops in Europe, nor the ability to move such troops which we didn't have anyway at that time, nor any request from the Europeans for a massive army to fight Hitler. Thus, our consenting to appeasement was unavoidable. We did see the threat and start a massive build up to defend ourselves. The suggestion that we should have started that earlier to invade Europe or land troops there proactively was never going to happen.
3. Russia could probably act against the Baltic Countries or places like Georgia and they have against parts of the Ukraine. They do not have the forces or structures or economic resources to do a 1980's style invasion of Europe proper. To cross into the Nato countries or major neutrals like Finland or Sweden and then further in the older Nato countries like Germany or France is far beyond them.
Such a great war would be a large economic strain and has to be backed by the people. I doubt that support exists in Russia.