I've never heard "texture" used this way, although that's not saying much. My personal opinion would be that it's not the right word. I have heard the term “color” used in typography to describe the balance of positive and negative space on the page in phrases like “even (or uneven) color”. But although that feels closer, it also doesn't feel quite right in this case. It reminds me of the subtle changes in tracking and glyph width that some justification engines perform:

“Most of the type set in the past five hundred years is justified type, and most of it has been justified line by line, by the simple expedient of altering the space between the words. There are, however, better ways. Scribes justify text as they write by introducing abbreviations and subtly altering the widths of letters. Gutenberg replicated the feat by cutting and casting a host of abbreviations and ligatures along with multiple versions of certain letters differing modestly in width. In the early 1990s, Peter Karow and Hermann Zapf devised a means of doing much the same in the digital medium[.] [...] Another thing computer software can do – because Karow taught it how – is justify text by making subtle alterations in the spaces within letters as well as those between letters and words.”

The Elements of Typographic Style, fourth edition, by Robert Bringhurst, pp 191–192.

I think "texture" makes sense, if only by analogy to the calligraphic hand Textura, or the etymological derivation of "text" itself.

I'd call it dynamic monospace.

Duospace fonts are limitedly proportional, but still with no upsides of monospace fonts. Rather than that, I recommend something more proportional like iA Writer Quattro, Input Sans and Recursive Sans. https://input.djr.com/ https://www.recursive.design/