Do not declare war on the United States. The United States will have to wait until Round 3 to join the war
Round 2: Italy holds off the British, Japan pushes into China, the money islands, and the Soviet Union, and Germany pushes into the Soviet Union.
You cannot take the money islands without going to war with UK and ANZAC. You cannot go to war with UK and ANZAC without bringing the US into the war (unless they declare war on you, but they won’t). From page 37:
Japan may attack Dutch territories only if a state of war exists between it and the United Kingdom and ANZAC.
The United States may not declare war on any Axis power unless […] or Japan makes an unprovoked declaration of war against the UK or ANZAC
I think leaving the money islands so long is a handicap the Axis just can’t afford. Worse, ANZAC and the UK can take these islands for significant income boosts.
Rules aside though, I think you’re wildly underestimating Russia. An average Russian player will not lose Moscow on turn 5 or 6. A good Russian player will actively force Germany to delay movement or risk attack-retreats strongly in Russia’s favour. Germany’s advantage here is that Russia cannot afford to guard all of it’s critical territory and will eventually bleed out when it loses enough income.