> That's a simple example, but if the AI is superhuman, I don't see any reason why it cannot break things down into simple concepts. I don't think anything is truly beyond comprehension; it just needs to be explained properly

You should try being a teaching assistant or a tutor. "Everyone can be taught everything, it just depends on the teacher" can only be said by someone who never tried this in practice. Just as not everyone can learn advanced math, the best mathematicians also have their own limits and there are things they won't be able to understand or comfortably navigate. Not just because it's a lot of material, but because it's complex inherently.