I think the bigger anchor around Germany's neck was the alliance with Italy. Granted the Japanese didn't help out against Russia, but they also didn't bring the USA into the Second World War... immediately after Pearl Harbor US Isolationism was still fierce with public sentiment being 'we have our war, they have theirs' and were not drawn into the European theatre. It took Hitler declaring war against the USA a week after Pearl Harbor to do that.
In the meantime Italy's failure was why the Germans ended up in not only North Africa - but their failure against Greece brought Germany into the Balkan campaign... thus delaying the start of Barbarossa... and it was that delay that cost the Germans dearly at the gates of Moscow as General Winter claimed the battlefield denying a victory over Russia that was so near.
The japans were big traitors. They didn't helped Germany against Soviet Union , and because of them Germany declared war in U.S.A.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.