On estimating the IQ of people who have not taken an official IQ test (Like Nikola Tesla and so on)

How possible is it to infer IQ through achievements? I mean I was thinking of Terry A. Davis, made his own programming language called holy c and made an entire operating system using it called templeOS. (unfortunately, he had schizophrenia and he died a while ago RİP) Most people who don't really have an idea of what cognitive testing looks like resorts to concluding that every major scientist out there is 200İQ+ (which I feel is extremely baseless, also iq most definitely has a diminishing returns effect say past 150-160, right? that's another interesting question.) Could we say that a person with a theoretical physics PhD from MİT is probably 125+? How well and much can we estimate IQ through these sorts of achievements?

What do you think?