A slightly pedantic point, but I assume you meant the Maldives vs. the inside lagoon of Bora Bora which is somewhat limited in sea life because it’s ultimately just a pile of sand. French Polynesia overall has a claim to the most extraordinary sea life in the entire world. The Maldives has some nice enough reefs and can be a good place to see whale sharks and mantas, but I’ve never heard it referred to in the same vein as French Polynesia. Go visit Fakarava, to name just one hotspot.