on your '39 varient i don’t know. on my set ups and map, yes it is too much. IJN turn 1 with my setups, IJN rolls over their competition while still being ambitious, with minimal losses.
if your pacific is close to mine still, then you will see. Set up your board with IJN +Anzac + US pacific forces only. Attack with Japan and just see what you can/could do with a Sneak attack. Now take into consider the possible ramifications globally that can help or hurt your side.
A sneak attack would allow japan easy island conquest with minimal forces, while setting up a super sweet turn 2 and invade HI. US would have left, if japan does it correctly 3 ships left in the pacific, no transports, no land units on HI. and possibly midway also.
in doing this, US has no choice but to respond, leaving Germany in a much better position.
I assume Russia and IJN have their treaty?
If they do, then that closes one front.
I apologize if this doesn’t help because if our set up charts are mostly different.