hi
this is an important topic
and thanks for the info provided in the post. It was useful for me.

"In reality, it seems that many people actually use both modes of thinking in differing degrees."

just would like to try to add something useful to the info already provided in the post.

According to the info provided in the book called "Thinking, Fast and Slow" by Daniel Kahneman.
https://en.wikipedia.org/wiki/Thinking,_Fast_and_Slow
there're 2 modes of thinking :
1/
fast
this one happens automatically. It evolves from the animals.
This type of thinking is the subject to errors/biases.
I suppose it corresponds to the thinking with the help of images/visual thinking.

2/
slow
This is the opposite of that mentioned above.
I suppose it corresponds to the thinking with the help of words/narrative.

So, I believe it's very unlikely that some people might have just the first one/one.
Because the 2nd one/both of them is what makes us human.

The research summarised in the paper
"Dissociation of Mechanisms Underlying Syllogistic Reasoning"
(https://pubmed.ncbi.nlm.nih.gov/11034858-dissociation-of-mechanisms-underlying-syllogistic-reasoning/)
provides some evidence/basis for the info given by Kaneman.

According to that info, there're 2 theories of thinking:
1/ mental logic
"The claim here is that deductive reasoning is a rule governed syntactic process where internal representations
preserve structural properties of linguistic strings in which the premises are stated."
I'd say it's like in programming we have the words (if, then, function etc.) which are part of the programming language itself.

This theory corresponds to narration/inner-voice mentioned in the post.

2/ mental model (developed by Philip N. Johnson-Laird. He wrote a book called "How we reason")

" The claim is that deductive reasoning is a process requiring spatial manipulation and search.
Mental model theory is often referred to as a spatial hypothesis and predicts that the
neural structures for visuo-spatial processing contribute the basic
representational building-blocks used for logical reasoning"
This theory corresponds to visual thinking.

As far as I know, the authors of the paper came to a conclusion that both theories works together.
which corresponds to the statement given in the post
"In reality, it seems that many people actually use both modes of thinking in differing degrees."

"And now, the obvious discussion question."

"What mode(s) of thinking do you use?"

I believe I use both of them.
Visual Thinking happens in the first place and then with the help of language I can correct errors/biases produced by the fast automatic visual one.
this is what I think happens in my mind.

As for "A second article that I found, An asymmetrical relationship between verbal and visual thinking:
Converging evidence from behavior and fMRI is behind a paywall, so I could only read the Abstract, which says:"

I downloded it here
https://scihub.bban.top/https://www.sciencedirect.com/science/article/abs/pii/S1053811917302379

click "сохранить" on th left if the download didn't start.

Sci-Hub
https://en.wikipedia.org/wiki/Sci-Hub
https://scihub.bban.top/

they periodically shut down it, so there's
https://whereisscihub.now.sh/

allows to get access to all the papers/articles.

I understand it's not very good, because scientists need money.
but sometimes I think we can use it if we really need it.
I suppose in the near future blockchain will allow scientists to get $ for their efforts
so that they wouldn't need to set paywalls.