This is nonsense. The human mind cannot visualize more than 3 dimensions. It can perfectly comprehend any number of dimensions as long as they are represented in a vector space. In fact, that's what linear algebra does.

I think you accidentally a word, there. GP is talking about comprehending the capacity of massively multi-dimensional space.

I think the human mind can visualize anything, eg here are some visual descriptions of higher dimensional objects: https://gfody.substack.com/p/mini-hyper-golf

Yes. It's worth pointing out that anything with n distinct parameters is just a point in n-dimensional space. We're so used to handling so many dimensions that nobody ever bats an eye until someone brings up the magic word "dimensions". It's quite intuitive actually.

The trivial example that comes to mind is the character customization sliders in many video games.