I've been to Cuba, Martinique and Cancun.
I stayed at an all inclusive in Varadero, Cuba and I really liked it. The beaches are absolutely gorgeous there. The resorts are pretty nice with lots of activities. You can also do some sightseeing around Cuba with organized tours. There's lots of good rum and great cigars. However, you don't eat well in Cuba. They don't have a lot of food and whatever good food they have, they serve at the resorts which says a lot about what they have. The people are poor and if you have any degree of sympathy, you'll feel bad for them the whole time you're there. And they remind you how poor they are all the time.
In Cancun, Mexico you have to pick the right place or you'll get a beach full of rocks. I stayed in the hotel zone at Sandos and the beach was gorgeous. The food was great! Lots of activities and animation and shows. There's less sightseeing though. And the food on site is pretty American in flavor. If you're a bit more adventurous, you can take the public bus for super cheap to go into Cancun city in the evening and they have a park, the Parque de las palapas, where they have tons of street food. You'll eat amazing Mexican Street food for amazingly cheap. Even if they charge you the gringo price. There's also a shopping mall in the hotel zone which is huge if you want to do any shopping. Honestly this was my best experience in an all inclusive resort.
Martinique is a French territory. If you don't speak French, you'll have a difficult time there. Otherwise, Martinique is a god damn jewel. I've never seen beaches as gorgeous as what's there. It's a real life paradise. I spent time there doing a bit of a road trip across the island. We visited multiple beaches and stayed in hotels and Airbnbs with hosts. They have the best rum I've ever tasted and there are plenty of distilleries you can visit. There are a lot of boats you can take with a group to more remote locations to do some snorkeling, but many of the beaches in general are already great. The food there is fucking fantastic! The French being big on cuisine really had a big influence there. The Creole food and seafood is out of this world. Accompanied with great wine and rum to boot. This was one of my best trips honestly.
This year we'll be going to Panama. I haven't found a good resort yet that has a good beach. And they're all far from any airport or city so not very accessible. I don't really know what to expect there. I'm going with an open mind and we'll see what happens.