If Japan has to spend $ on fleet to counter USA and troops on mainland Asia Allies are probably winning.
Japan has to eliminate UK quickly so it can concentrate on USA. Defeat your enemies in echelon.
Going for ANZAC is a deadend. The IPC’s are just not worth it and your forces are now out of position to counter the other Allies moves.
Safest strategy for Japan is take India first then position forces on Truk so you threaten Queensland and Hawaii simultaneously.
Then again, I strongly advocate a J1 attack. Maybe someone has a more optimal strategy for a J3 attack.