I don't see how you can do this without finding a way to convincingly cover up the majority of the Holocaust or finding a way to pass equal blame on the Allies--probably a mix of both. Even at the worst the Allies can get--probably involving things like Operation Vegetarian, worst-case Decisive Darkness-type Operation Downfall, and Soviet war crimes cranked up to 11, it's pretty hard for the aggressors of the war who fought for territorial expansion, committed endless war crimes in China, Asia, Eastern Europe, topped off by the Holocaust, to be portrayed as anything but "equally evil" at best. And it would take decades after the war for the Allies to be perceived as equally bad, like maybe in the 60s more attention is drawn to Vegetarian, Downfall, etc. and the excesses involved and the Western Allies begin to question their role in the great evil of WWII and consider themselves not much morally better than the Axis or the Soviets, although such criticism would no doubt be considered communist subversion on the part of the USSR.