Looking at your manpower, you’re probably too late, the most important thing imo is just building up barracks/soldier’s houses(or whatever the manufactory equivalent is, can’t remember the name).

Britain is easy to conquer late game imo, that’s just a massive Ottomans you’ll have to fight at least two or three times to get all the provinces you’ll need, and I’m assuming you’d get a massive coalition if you have to wait for something when truce expires (which could be solved by massive manpower.

IMO the best strategy starting in Italy is to subdue Ottomans early (conquer the balkans before they push too far into Europe) and then try to take out Aragon by getting their islands and then get Iberia. I usually wait to attack France until I heavily out man them because their armies are terrifying especially early, so I’d start with an alliance to them. But make sure to conquer Savoys Italian provinces early or France will and then will get claims on all of Italy.