Of course this leaves unanswered the question of why math not only works internally, but also describes our world so well. Maybe we'll learn the answer in time.

Aargh! Every time I come across this argument, I am frustrated that people don't see how this 'problem' is resolved. Even Einstein is said to have remarked on the 'mystery' of why the world is knowable.

We ditch the 'explanations' that don't describe our world well, and keep those that do. That's why our models end up looking like the world. When new data arrives that isn't compatible with those models, eventually we end up discarding them and creating new ones.

There is never any guarantee that some phenomenon we come across won't be beyond our ability to understand. There is never any guarantee that any model we possess is an accurate one, no matter how useful it's been in the past or how well it accounts for known data.

There is no mystery as to how we can know the world. We don't.