It is widely known that Maya civilizations worshipped many gods so why would Joseph Smith have referred to the “great spirit” in Alma 18:24-28?
And Ammon began to speak unto him with boldness, and said unto him: Believest thou that there is a God?
And he answered, and said unto him: I do not know what that meaneth.
And then Ammon said: Believest thou that there is a Great Spirit?
And he said, Yea.
And Ammon said: This is God. And Ammon said unto him again: Believest thou that this Great Spirit, who is God, created all things which are in heaven and in the earth?
While it may have seemed anachronistic at the time of the Book of Mormon’s publication, the “great spirit” fits well with the chief god U K’ux Kaj (Jurakan) who was believed by the Maya to be the great creator.
How would Joseph Smith have known this? Wouldn’t he have used many gods if he had written the Book of Mormon himself?