Most Latter-day Saints are persuaded by their CES and BYU professors who tell us we are “sophisticated” because we are learning from with PhD archaeologists, linguists, geologists, etc., instead of relying on the naïve speculations of a bunch of 1830s farmers (who happened to be ordained prophets and apostles, but were merely expressing false opinions about Cumorah)
But when we re-read the text, we can see that these verses describe different features. They were written at different times, from different perspectives, and even used different terminology.
Look at what the text actually says:
32 And now, it was only the distance of a day and a half’s journey for a Nephite, on the line Bountiful and the land Desolation, from the east to the west sea; and thus the land of Nephi and the land of Zarahemla were nearly surrounded by water, there being a small neck of land between the land northward and the land southward.
34 And it came to pass that they did not ahead them until they had come to the borders of the land Desolation; and there they did head them, by the narrow pass which led by the sea into the land northward, yea, by the sea, on the west and on the east.
9 And he also sent orders unto him that he should fortify the land Bountiful, and secure the narrow pass which led into the land northward, lest the Lamanites should obtain that point and should have power to harass them on every side.
7 And there they did fortify against the Lamanites, from the west sea, even unto the east; it being a day’s journey for a Nephite, on the line which they had fortified and stationed their armies to defend their north country.
5 And it came to pass that I did cause my people that they should gather themselves together at the land Desolation, to a city which was in the borders, by the narrow pass which led into the land southward.
20 And they built a great city by the narrow neck of land, by the place where the sea divides the land.
We have a small neck, a narrow pass which led by the sea, a narrow pass that doesn’t mention the sea (Alma 50:34 and 52:9 could be referring to the same feature, but not necessarily), a line, a narrow pass described hundreds of years after the Alma reference, and a narrow neck of land.
To be sure, these passages could all refer to the same feature, but as a rule of construction, a reader should assume authors use different terms to refer to different things. For example, a “narrow neck” commonly refers to a water feature. That’s why Ether 10:20 specifies that it was a “narrow neck of land.”
Throughout the Book of Mormon text, authors are writing from different locations at different times. To assume each of these references describes the identical feature is to impose an interpretation that the text does not require or even suggest. Not impossible, but not likely, either.
Certainly, this strained unitary interpretation is not so mandatory that it justifies rejecting the words of the prophets and apostles about the location of Cumorah.
You see from the above citations that the term “narrow neck of land” is used only once in the entire text, in Ether 10:20.
The term “narrow neck of land” is inherently subjective. Here’s a great example.
Ron Chernow recently published a book titled Grant, about Ulysses S. Grant. At Kindle location 9161, Chernow writes, “[Gen Beuregard]…driving him [Gen Butler] back down the river to a thin neck of land formed by the confluence of the James and Appomattox rivers.”
To what geographic feature is he referring?