Well, here is what GPT-3 can say about the secret:
There is no clear answer to what the secret of Monkey Island is, as there are many possible interpretations. Ron Gilbert, the creator of the Monkey Island games, has stated in interviews that the secret of the island is meant to be open to interpretation and that there is no one correct answer. Many of the characters in the games express their own theories on what the secret may be, but none of them are ever confirmed or refuted. It is up to the player to decide what the secret of Monkey Island is, if there even is one.