First, come up with a strategy for Germany, and then one for Japan-you control the respective powers from the start of the war, with these restrictions:
The Axis cannot not go to war with France, the Low Countries, and Britain.
The Axis cannot conclude a separate peace with China.
Other than that, you control all military forces (with no intervention from anyone), and you have the ability to declare war (or not) on the Soviet Union, the US, and all other countries. So how could the Axis have won the war? I’m looking forward to your thoughts!