Your challenge, if you choose to accept it, is to, with a PoD no earlier hen June 22nd, 1941, make Operation Barbarossa go as badly for the Germans as possible. This means: land taken by the Germans and Allies; the loss of men and machinery ratio is as skewed towards Germany as possible; and, unless here is a good reason for the USSR to make peace, the quickest absolute Allied victory as possible.
Go!