>Maybe some of them are like finding the 1 millionth digit of pi.
Yes some of them were clearly like that but there are probably 5-10 which many mathematicians have said were massive results and would all but guarantee a Fields Medal to any human that had solved them. Navier Stokes, Quasi Riemann, etc.
Now that we have LLMs, those that are hard for people but easy for LLMs will get cleared out, leaving those that are still hard for both.