It is funny to see this article today. Overnight, I was considering the question again of "Is the map the territory or not?" JadeNB refers to this in their comment.

What a lot of people do not see, including many theoretical physicists is that mathematics is a "map". It describes reality in a simplistic way, but is not the reality itself.

twlevechairs26 refers to the quote "All models are wrong but some are useful". This highlights the fact that all models are maps, incomplete, simplified descriptions that leave out specific parts or include things that are not part of the thing being described.

When we get arrogant enough to claim the "truth" in mathematics or science we have moved into the realm of religion. Mathematics and science helps us get a handle on trying to understand the physical universe around us. But it will NEVER, and I repeat this, NEVER give us perfect understanding of the universe around us. For that perfect understanding would require that we become greater than the universe around (in effect raising ourselves by our bootstraps to be God or gods).

So, in may ways, the first question here, "Is the map the territory or not?" before asking "Is the Universe made of mathematics?"