In my paper "The Book of Mormon as Literary Alchemy: Joseph’s Magnum Opus and the Philosopher’s Stone," I suggested that the "gold plates" that Joseph Smith had in his possession were not actually made of gold, and did not actually contain ancient historical records like Mormons traditionally think. But that doesn't mean that there were not "gold plates" which were a kind of "hidden treasure" that Joseph really did discover within himself, which was the source of real divine wisdom, "ancient wisdom," and which he taught could be found within all people as well.
Two readers posted comments recently on my article about Joseph Smith as tertön and the Book of Mormon as terma. They were both similar in questioning the idea that the Book of Mormon may not be a historical text.
I suggest that the translation of the Book of Mormon was Joseph Smith's alchemical Magnum Opus, or "Great Work," a transmutation of his own base desires for materialistic gold and treasure into the highest spiritual realizations of human atonement in God consciousness, and a realization or awakening of eternal life in his Self, even theosis, which he continued to preach for the rest of his life.