Holy shit, this has to be one of the most difficult proofs to formalize due to it's length and complexity right?
Yep. There may be only 25-50 people alive today in the whole world who can credibly claim to understand Wiles' proof. Now we add an LLM to that list. Absolutely mind-blowing stuff.
not really. it's one of the most difficult ones so far for sure, but pales in comparison to something like the classification of finite simple groups.
This was initially "completed" in the 80s. You can see the timeline for cleaning up the proof in e.g. this mathoverflow answer
https://mathoverflow.net/questions/114943/where-are-the-seco...
it's something that some people have been waiting decades for, and is not yet completed.