cruising these days really isn’t like the perceptions of old.
There’s a cruise line to suit almost every taste, and on the big ships the entertainment now is really high quality, with loads to do. In many cases shows will be almost west end standard, and then you’ve got all sorts of other options depending on the ship, from escape rooms, to rock climbing walls to ice rinks.
A large cruise ship is like a floating resort - and generally much better than you might get on an all inclusive type resort - with more choice and variety of restaurants, bars, entertainment, lounges and activities. You also have the benefit that you’ll dock somewhere almost every day, so you can get off the ship and explore new places, but with no hassle.
The rooms may be smaller as standard than you might get in a beach hotel, but if that’s important to you then there are family suites and larger rooms with balconies.
I have no personal experience of cruising with kids but I’d generally have thought cruising is a very good option, as they’re a contained environment with lots of child friendly options as well as kids clubs etc.
As others have said, it’s worth doing some research as there’s a huge spectrum now in terms of cruise line and what they offer.