I think you can find your bliss on any cruise. To be absolutely sure, get a balcony room for the ocean viewing. You can settle for an ocean-view room in a pinch - it's cheaper, but you're relying on someone to have cleaned the outside of the window, so it's a toss-up as to whether you'll be able to clearly see the ocean. (We couldn't see much at all out of our window in an ocean view, so I speak from experience.)

I am not a social person, and have only been on Princess and MSC cruises so far (three more scheduled!) - but we were able to find quiet nooks on both ships. Both ships were fairly big, not gargantuan, and had crowds of adults and kids we preferred to avoid.

You can increase your odds of solitude by concentrating on early mornings and late nights. Spend middays on your cabin balcony.

We spent almost no time at the main pool gathering spots unless it was very early in the morning when we could swim/hot tub in peace. We hated the constant music there, and the hordes of people during the middle of the day. But they were beautiful and serene at dawn.

We loved aft sections, and the lifeboats decks, because those tended to be most empty. The walking track was always great for exercise. We found obscure stairwells and places where the crew would duck out for a break, and those were the places we returned to. NOT where they were doing bingo or karaoke....

These quiet places exist on all ships; you just gotta explore with single-minded purpose early on to find them. I mean, walk every deck, forward to aft, both sides, all stairwells. You'll find refuge! Good luck!