For several years, my team and I have been working on a 1945 setup called “The Game to End All Games.” It follows what would have happened if Russia remained neutral and Great Britain fell. China and India are considered to have signed a separate peace The main Axis power is Germany which controls most of Western Europe (Eastern Europe, Russia, and mainland Asia are out of play), Iceland, French Equatorial Africa, Gibraltar, and Nigeria and Gold Coast. Italy Controls Egypt and East Africa and is poised to march to South Africa with a German expedition to Free French Cameroon and Vichy (a new minor power) troops supporting. South America has United and is a new playable ally. German navies are ready to attack the Americas anywhere. Meanwhile, Japan is planning to attack Australia and Hawaii and Alaska.
For potential inspiration, you might want to have a look at interesting (but short; it’s only a page long) essay by David Fromkin in the book “What If? : The World’s Foremost Military Historians Imagine What Might Have Been”. The essay is called “Triumph of the Dictators”, and it points out that in early June 1941, just before Barbarossa, most of continental Europe and large portions of Asia were under the control of the Axis powers and of either their allies or of powers with which Germany and Japan had non-aggression pacts. It paint a grim picture of the U.S. and of the surviving democracies as being (if I remember Fromkin’s phrase correctly) isolated in a hostile world.