I have a degree in Russian History and Russian Language.
I did a major thesis on the 900 days in Leningrad and some of the battles around Mga.
I get some grief, but I really believe that Germany was already defeated by Russia because of Stalingrad.
If we had stayed out, Russia would have eventually taken over Germany, but it would have bled them to the point that they would have fallen apart much faster and Eastern Europe might not have suffered as they did.
A resurgent Czechoslovakia or Hungary, aka 1956, would have destroyed the Eastern European coalition and brought about the end of the Soviet Union much faster.
Uhhhh, no......
The Soviets have long insisted that Lend-Lease aid made little difference. Newly discovered files tell another story