Its just assaulting coasts with militia is essentially impossable against the various Pacific islands, England and if the USA has coastal defences. The Germans were the main point, the Japanese a bonus. It was very difficult getting the last Japanese islands with complete air and navl supremacy and 40+ militia for each islan in waves of 6 vs garrison soldiers. Truk has 9 divisions of presumably 1943 lvl infantry.
The Allies can't really touch me in the USSR proper, even if I let them in. I would probably wi eventually but Its more interesting to play Manchukuo. World conquests I find boring as it becomes redundent after a certain point and its only a matter of time.