This strategy depends also what is the allies doing.
You should not build a minor factory in Greece, just use your rail way capacity.
The most important thing is:
Italy and Germany should move as one.
So for example if Italy in round 1 takes Alexandria Germany can send in round 2 some fighters to support Alexandria. So Italy makes a move and Germany follows. In this way the allies cannot counter attack because you would be to strong in this stage of the game.
So round 1
Germany builds up 5 sup
6 waffen ss infantry and 2 waffen ss artillery.
Italy builds 2 landing craft and 1 paratrooper in Rome.
Round 2 Germany likely will have 85 ipc
So you should build:
8 paratrooper/ can jump to Italy. Or Romania.
1 panzer general.
2 landing craft /// strategic rail movement to greece
5 subs // 3 in the mediterranean, also Remember if you move you’re “remaining” italian ships to seazone 93 to eliminate the French ships, you can use the factory with Germany to build subs or a carrier in that seazone to counter the remaining British fleet.
The best thing which could happen is that the British attacked the Italian fleet in round 1
The Russian plan is to take out Novgorod as fast as possible, butt in round 5 you need to retreat till you’re own borders this is okay.
By that time Germany can build up a huge force, and push again.