You have not to go at war at all to win by 1948. Military and economic power is also part of the fraction victory system. Just build up an enormous industry as germany and sweettalk everyone for trade agreements to get the needed resources. In 1941 put some IC to build 100 aircraft carrier or 400 tank divisions if you prefer. Use your spies to increase badboy rating of SU and UK. Get everyone else into your faction. The Allies can't dow you because of their neutrality. So there is no point to go to war as germany. The best way to win the game is to be peacefull.