At the core it seems to me there’s a strong difference between abstract thinking and any particular verbalizing or visualizing implementation of it. I’d even venture to say that visualizing and verbalizing are slower, less precise methods to approximate the optimal thinking strategy of “knowing the answer already”, as compared to the non-visual/verbal methods that aphantastics/anendophanstatics are forced to use (and if others use it to some extent, it must be without realizing it based on their inability to comprehend aphan/anendo minds).

Evidence for the claim? When HN user Lerc describes gameplay analysis: "They want to do this, but they feel like doing that directly will give away too much information, but they also know that playing the move they want to play might be interpreted as an attempt to disguise another action", it’s very clear that this sort of long winded verbalization of a thought process is not the ideal mental exercise, my impression is that Lerc’s mind is able to do that entire exercise much more quickly and simply know the answer, and know that it could be verbally justified if needed, without wasting the time to verbalize that a priori. This is that indescribable thinking approach.

Similarly, I personally am aphantastic and things like navigation come very easy to me, a surprise to many. (I’ll admit i’m not a great speller, but neither is my dad who has a very visual mind). Moreover, I’m a moderately talented hobbies woodworker and it’s very easy for me to think through the full construction details of most any project, going down to any level of detail required and coming up with solutions to any relevant corner/edge cases, all internally without any words or visualization. I don’t have many people to compare this act to as it’s a fairly solo endeavor, but I do know that one person I made a project for has a very visual mind and is able to do that full “solid works in my head” visualization process. However, when we talked through a project she wanted together I pointed out several conflicts and ambiguities that she did not understand until I drew up the plans on paper.

Also, it’s worth bringing up the classic “bicycle test” as evidence the standard “visualization” method is woefully inaccurate: nearly everyone has seen a bike at some point in their life, but when asked to draw it provide absolute nonsense. Aphantastics, in my experience, never fail to sketch out a fully mechanically sound contraption. Pointing again to the idea that we somehow are closer to that platonic idea though process of knowing the answer than typically visualizers.