Limiting our scope to just the length of the Book of Mormon, shouldn’t our starting point be that it is unlikely a first-time author like Joseph would have produced such a long book on his own?
In 2021 Kyler Rasmussen analyzed 116 authors with prominent literary works published between 1800 and 1860 and compared:
Just looking at page counts, Joseph Smith was a clear outlier. He was younger than average, had substantially less education than average. Taking that into account, he produced a work far larger than anyone would have guessed (around 531 dense pages).
Isn’t the length of the Book of Mormon a simple piece of evidence that Joseph Smith likely did not write it himself?