The Ukrainians in particular welcomed the Germans as liberators. If the Germans were smart they would have recruited them against Russia but Nazi doctrine regarded them as “untermenschen”.
They also could have recruited General Vlasov.
Actually that set up my “Best Case Scenario” for the war, and it almost happened but Hitler (wisely on his part) rejected allying with Vlasov.
But I could have seen Vlasov’s army helping to overthrow the Bolsheviks, then immediately turning around and fighting the Germans back.
Hitler and the Bolsheviks both go away...if only it could have been.