If the Germans had played their hand different, they may not have had a partisan issue. Many of the ethnic groups did welcome the Germans as liberators. Remember, many of the Germans were former socialists who grew up hearing about the worker's paradise, as per the books SOLDAT, FRONT SOLDAT, WAR ON THE EASTERN FRONT (Lukas), and other Landser's memoirs of the past 15 years.
Also bear in mind that the SS had units of Ukrainians, Georgians, Cossacks and even people from some of the southern Islamic areas. These units fought Stalin's partisans. Understand that Stalin murdered 12 million Georgians and/or Ukrainians.
Russia would have afforded the Third Reich vast resources equal to the US and UK.
It would all come down to how the Nazis would administrate the country. If the "Golden Pheasants" treated the populous as they did, there would have been severe problems. If they had the sense to be more benevolent and continue the "Liberator" policy, the Russians probably would have joined with them, at least in part. After all, do we really think that a mere 20 years completely erased all the anti-Bolshoviic / Imperial Russia / White Russia V Red's animosity that lead the US, UK and France to send supporting armies into northern Russia 1919-1922?
Bear in mind that early in the occupation of France, a lot of the French accepted the Germans. Quite simply, one reason that France disintegrated so fast in 1940 was France had deep political divisions, Fascist, Communist, and democratic groups, as explained in Keegan's BLITZKRIEG or the book BLOOD, SWEAT AND FOLLY. Not only that, but until Barbarossa, commie groups in France and England were inhibiting the war efforts at the direction of Stalin.
Now we really get into the "what-ifs". Had Germany attenuated the resistance in Russia, they would have a landbridge to Iran/Iraq, where they had assisted in a rebellion in Iraq against England. Additionally, there was the independence movement in India, which the Japanese actually exploited. Caucus & Persian Gulf oil, a rail network to the Pacific...
Referencing
World War II casualties we see Japan's 1939 population was 72,000,000. China's was 530,000,000, a 7/1 disparaty. Japan dominated China. Why? China was also divided.
Fortunately, we will never know what would have happened had Black Fascism beaten Red Fascism.