The partisan will raid convoys and settlements for food, almost constantly.Wouldn't it be pretty simple to starve out the partisans? Especially in a war of extermination?
Even if the Germans manage to drive the Soviets to the Urals as per their plan, all those weapons the Red Army left behind will be quickly utilized by the partisans.
My great-grandfather's Chinese partisan unit often raided Japanese convoys and supply bases for weapons, supplies, and medicine.
It was simply impossible to catch them because the Japanese could never anticipate where they would attack and when.
My grandfather told me that his father (my great-grandfather) would mark down the locations of Japanese supply lines and supply bases and then randomly point to a base when his guerillas were planning a raid.
It was just so random, the Japanese could never figure it out.
According to my great-grandfather's journal, they (the Japanese) were like the blind men in full daylight. They could never figure out his strategy because there was none. Just pure random attacks.
The Soviets will do the same thing to the Germans.
And it will be effective as hell.