I’ve been able to win Africa as Germany a few times. The problem is that it relies too much on luck to be a strategy. I believe that as the Central Powers, you have to “rush” Paris ,Moscow, or Rome before the UK and the US land in force. Once the US lands in Europe, Allied victory is very easy.
Some key points for the Central Powers
The Ottomans need to keep British and Possibly Russian and French Units tied down in the Middle East.
The Austro - Hungarians need to push into Italy to capture Rome and push Russian Units back to help the Germans
Germany “rushes” Paris and Moscow, as getting “bogged” down is what destroyed the Germans in the real war. Destroys the British North Atlantic Fleet, and does as much as they can to keep units occupied in Africa.
Some key points for the Allies
The French need to hold their ground, as they cannot push the Germans back far enough without British help
The UK needs to help their Allies wherever they can, put a majority of units in France, don’t leave too much tied up against Germany in Africa and the Ottomans in the Middle East.
Italy fights Austria and is on the back foot quickly if they don’t hold out with defense
Russia needs to draw all three Central powers’ units into battle with them to give time for the US to go to war
US supports where ever they are needed
This is all I have for now, as I’m leaving, I’ll be back.