while I haven't read DFW, it was because I was suspicious of his motives even in the 90s. the article leads with how he studied "modal logic," as an undergrad, which I only know of as a tool from a theorist named Kripke to reason about systems of logic that don't need external consistency or to produce arithmetic. it was taught in cultural studies programs as a justifying rhetorical "what-aboutism" for neutralizing appeals to logic, a kind of critical theory of math to unmoor people from the authority of math or anything objective, and to guide them to adopting subjectivity. What made me suspicious of DFW was he seemed to be doing just another variation of what L. Ron Hubbard, Richard Wagner, Karl Marx, Osho, Nietzche, and other attempted inventors of religions were up to, and Kripke's modal logics are a tool for producing these logics-of-ideas, a way of writing new pop-ideologies the way we write songs. DFW seemed like a hipster demagogue to me.
another artist whose work may be more rigorous in representing ideas from math is Arvo Pârt. even though there are more concrete things in his work than DFWs that you can logically decode, derive, and then transform and expand on them, much of what I've read[1] is still a bunch of woo that uses talking about "math" as a kind of mystical jibjab to elevate other ideas. Pärt worked as a sound and radio engineer and there is some reason to believe he used that practical knowledge in composing, because the logic in the music is very explicit. (visible triangles and linear functions, he has provided sketches of, etc)
there's a difference between writing something that is a metaphor for a mathematical idea as a vehicle for something else, and something that directly encodes the idea where you could derive it again from the thing you've produced. Maybe DFW did that with the Sierpinksi gasket, but I don't get the sense from anyone that he did. I am not a mathematician at all, but I do think if the idea is not independent of the language or representation it's made in, it's just another metaphor and a vehicle for the author.
[1] https://www.cambridge.org/core/books/cambridge-companion-to-...