my views on "苏联独自在欧洲战场打败希特勒"

I want to state the situation from different perspective.

Let me assume that Nazi Germany allied with the US and Great Britain.

1. Royal air force fought against the Russian air force instead (the Russian AF were basically wiped out by the Germans in 1941 anyway). The US would bomb the Russian cities instead of the Germans'.

2. Battle of Atlantic didn't happen & Africa was under control of Germany and the Great Britain. The Germans got shipments of precious war materials from Africa & trucks/boots from the US in addition to weaponry. Economic sanction was imposed on the Soviet Union not Germany. The Royal navy and the German battleships blocked the Russian coastlines.

3. The US assisted the Japs to organize another invasion from the south of Soviet Union (new front).

4. The US attacked the Soviet Union from the East instead of landing on Salerno, Italy or Normandy, France, to open up a new front.

Are we still confident that 苏联独自在欧洲战场打败希特勒?