No offense, but the fact that you have 1000 hours of play and still pick major powers (and have a hard time with them) goes to show that you are NOT a good player.... I have 1061 hours into the game, and I think for the last 800 hours I haven't played a game as any major power because there is no challenge in it. The strongest start I did was probably Scotland, and that was already kind of too easy (for the Reversed Auld Alliance).
For example, even if a peace deal with give you like 40 AE with nations you can easely make sure that no major power joins a coalition as long as you have them improved by +/- 100 (that easely offsets the agressive expansion), heck, I have had multiple great powers with >70 AE and still not joining coalitions against me. It is also not wrong to keep a war going a little longer to get the relations improved with the people that you might fear in a coalition.
Second, losing your navy to Mamluk + Venice as Ottomans is just plain out stuppid (no offense) there is no need to ever lose your entire navy like that... Just don't engage if you are outnumbered like that. If they engage you, retreat right away, recover at port and as soon as you are fully healed, engage them again, retreat as soon as you can, so that you don't lose ships, heal again and engage again... AI is extreemly stupid with ships, they often don't go back to heal or they split up their ships, so you can just to hit and run tactics and often destroy a fleet 3x your size without losing a single ship (ok, sometimes you lose like 1-3 ships)..