Lots of wonderful places to go and things to see, and prudently stay on the ground. I view Cruise ships as unnecessary hedonistic luxuries. The only one been on that was actually interesting was an Alaska Cruise
YMMV
There are other smaller ships other than these mega ships so heavily advertised.
Check out American Cruise Lines. They go up and down the Mississippi River, the Columbia River, the east coast of the US. In the winter the same ship that goes to ports in Florida offers cruises on the New England coast. Plus these ships fly the flag of the USA. Therefore, they have to abide by the laws of the USA(the Jones Act).
In addition there are smaller cruise ships in the Caribbean that have around 400 people on board. These ships are not cheap. All the rooms are really nice. Almost all the rooms are on the outside of the ship.
I went on my honeymoon 23 years ago on a Windjammer Barefoot cruise in the British Virgin Islands. This company went out of business after the owner died about fifteen years ago. However, there are still a couple of his ships that do the same thing under different names. These ships had about 75 passengers and 25 crew. They went to smaller islands where only private yachts went. They stayed away from the ports where the big ships went.