Germans had Guderian. World class armour warfare Marshal.
And a clown called Hitler who interfered.
Russians had winter, large land mass, defense in depth,
luring Germans into minefields, killing zones. 1000s of mortars.
Attacking Russia was stupid and not necessary.
Attack it and Russians will unite and galvanise against you. And fight you to the death.
See Ronald Reagan?
He was far superior to Napoleon or Hitler.
He could convince USSR to glastnost, perestroika and break up on its own; all without firing a single shot.
Truly a superior foe who as Sun Tzu said, can win without fighting.