General Patton took everything into consideration and was confident we could have beat them. I’ll go with Patton.
Also, unlike the Germans, we could have gotten a lot of Russians and Ukrainians to fight on our side.
Absolute nonsense! If the USA was 100% mobilized to fight the Soviets, maybe we could have won a conventional war? We had nowhere near enough troops in Europe to beat the Russians in 1945. The US Army had 80 combat divisions. The Russians had hundreds of divisions. Even if we had the troops, millions of American soldiers would have been killed in action. It would have been a bloodbath.
Soldiers, particularly American soldiers, are not automatons. This applies even more to American civilians.
There was simply no way for the Commander in Chief, even with the support of Congress, to launch a preemptive assault on the USSR. The people simply would not have stood for it, especially after several years of wartime propaganda lauding our gallant allies the Russians.
To paraphrase a famous writer on war, “War is politics by other means.” Among other things, this means that war takes place inside the political system and military possibilities are limited by what is politically feasible.
Lots of generals, including MacArthur and apparently including Patton, forget this. It is possible, though I doubt it, that launching nuclear war on USSR or a few years later Red China was a good idea from a purely military POV. However, it was simply not possible politically, and therefore would not happen.