I am in your same situation, getting back to the game after a while.
One thing I notice about Italy (which seems to be the country that you are having most trouble with) is that if they are not dealt with early in the game, they can be a huge help to the Axis powers.
I see a lot of discussions about doing or not doing the Taranto raid. For me it is a must. Otherwise the Italians can get a very comfortable position in the Mediterranean and be a headache for the rest of the game. It happened in the last two games I played.
Specially if the get their hands in Gibraltar and Cairo. Then they effectively block the Allies from getting in the mediterranean and get a lot of IPCs from their national objectives.
What I could not find yet was a solution if I am the Italian player and I get “tarantoed”. It basically keeps me off for the rest of the game.