The thing is, the universe and mathematics are totally separate entities. The universe did not start off "as math", nor is it defined by it.

We, as clever little beings found similarities and analogies between the universe and mathematics and leverage those to make conjecture regarding the form and nature of the universe. However, having a "complete" knowledge of either mathematics or the physical universe does not confer complete knowledge of the other.

Physics (and science in general) isn't about searching for the Truth. Instead it's about reducing the amount of error in the mental models we use to approximate reality. Like, when a scientist says "the Law of Gravity", they actually mean "our best current guess as to how gravity works, which seems to make accurate predictions in what we consider a statistically significant number of different scenarios, but which is incomplete and perhaps even completely wrong in several other interesting scenarios or edge cases". Only _everything_ in science has a confidence interval, and prefacing every description of some phenomena with the phrase "we're pretty sure this is how this works, but to be perfectly honest, it's only an approximation to some X degrees of accuracy" gets really exhausting, so for stuff we're really, really sure of, like 99.9999% sure, we call it a "Law" (even though it isn't) and move on with our lives.