To answer your question Barbados is the best island
How about a two centre? We did Barbados and Antigua for honeymoon.
Barbados - safe, easy to get around, lots to do - boat trips, caves, rum factory, gardens, museums, snorkelling, cricket, horse riding and racing, shopping, golf, beach clubs and the most stunning restaurants - literally the best restaurants in the world. Yes it can be pricey but if you get the right deal absolutely worth it. BA has had some great deals since covid. Most west coast hotels very good, south coast generally cheaper but still good. Some of the bigger hotels have all been taken over by Marriott but still good eg Tamarind. Independent hotels like Mango Bay, The Crane amazing. Cheaper ones like Southern Palms and Rostrevor.
Jamaica - is great and a fantastic vibe. Again lots to do eg Dunns river falls, blue mountains, Martha brae but you can only really go on guided tours not out and about on your own. Ocho Rios is best base to see the aforementioned things. Otherwise you want Negril for the sunset. Obviously there are places like Sandals and Couples resorts but they also have cheaper brands like Riu.
Antigua - probably the most beautiful and unspoilt but a bit boring, much less to do.
St Lucia - a reasonable amount to do but the island is harder to get around as essentially it's built on a volcano so depending on where you stay can be a long drive. Obviously you can go via boat around the island though. Areas like Rodney Bay have a lot going on.
Hope that helps!