So, the study is not actually out yet.
As the article says... its just a pre print.
A stage before the study is released, before peer review, etc.
What you are talking about is closer to the G Spot, which is even more poorly scientifically understood than the clitoris.
https://en.wikipedia.org/wiki/G-spot
Based on my uh, life experience so far, my hypothesis is basically this:
Some women have them, others do not.
Of the women that do have them, they can be somewhat different shapes and sizes, but are generally in the same area, and you can generally feel them to have a somewhat distinct texture to the rest of the inner vagina.
For some women, a G Spot orgasm is a totally different kind of orgasm than a clitoral orgasm. I've been told that verbatim from more than one woman.
This would indicate to me that... something different is happening to different sets of nerves, in some way.
Beyond involuntary muscle spasms/clenching, sometimes this triggers female ejaculation, sometimes it triggers basically a bladder release ("squirting"), sometimes it triggers neither.
Some women basically require significant g-spot and or significant internal displacement to consistently/reliably climax, others do not.
Sometimes it varies based on other kinds of stimulation... various combinations of different kinds of stimulation... whole bunch of other potential things.
And again, for some, significant volume and / or specific g spot stimulation is either not at all or hardly a factor in their uh, enjoyment.
The actual structure of the clitoris is much more substantial than just the little nub that you can see externally. Its a complex shape, its kind of molded around a bunch of other different parts of the vaginal area, just under the skin, internal, between other organs and tissues.
This is part of why it has been so difficult to map properly... theres a whole lot of anatomical complexity going on there.
(The other part is basicslly sexism).
Some theories are indeed that some women have clitoral nerves that extend either into, or closer toward the actual vaginal wall at the g spot area.
Others focus on the kind of inverted Y shape that the clitoris structure makes under the skin, essentialy straddling the vaginal opening... those are parts of the clitoris and do have nerves, and are moved and thus stimulated when something enters the vaginal opening, or manually stimulates the area.
Still oher theories focus on the so called "Skene's gland", or female prostate, as potentially playing an important role in reaching climax for some women, as well as potentially producing essentially vaginal lubricant and female ejaculate.
tl:dr;
Vaginas and surrounding environs are actually fascinatingly biologically complex, and at least to me personally, seem to vary to a significant extent from person to person, in terms of what their possesors find most pleasurable.