I went to ICFP in 2019, and I can say with a high degree of confidence that I was the dumbest person there [1]. Everyone was speaking on four-syllable mathematical notation that I had never heard of, and talking about intricacies in GHC that I wasn't really familiar with, and different aspects of type theory that were completely foreign to me.
It was very humbling; it didn't depress me or anything, but made me realize that there's a lot to learn and improve on, and the people there were actually extremely nice and gave me some pointers so I can get incrementally closer to being as smart as they are.
I think 2024 Tom would be the second dumbest guy in the room if I went again.
[1] Knowledge-wise, I have no idea about IQ or anything.