I’m not an expert on Angleton, although I’ve heard about him plenty over the years.
He was puzzle-obsessed, as I understand it. Like the people who were hired by the British to work at Bletchley Park during WWII, as codebreakers.
I know he eventually unhinged his own mind with all his hall-of-mirrors stuff.
I think Tom Clancy mentions his story in at least one of his novels.
Btw there are a ton of new Angleton documents in the recently released JFK files.
Among them were the unredacted testimony he gave to a Senate Committee in the mid 1970s in which he basically admitted he defied JFK and helped Israel get the atomic bomb.
While some of us “conspiracy theorists” had been claiming this for years after Seymour Hersch wrote his book on the Israeli nuclear program it is now a “conspiracy fact”.
If you want to go deeper down that rabbit hole you have to go back to World War II when Angleton was working for military intelligence in Italy and created a quid pro quo with Jews fleeing Europe. He helped them escape but in return got to use them as future intelligence assets.
As a result Angleton and future Mossad leadership had a close personal relationship which predated both the 1947 founding of the CIA and the creation of the state of Israel.
Angleton has a statue in his honor in Israel:
Bottom line: If the JFK assassination seems like a ridiculously complex “hall of mirrors” with a whole bunch of totally legitimate suspects that is at least partially due to the machinations of Angleton. It has his “touch”.