Go back to the real world classics from the golden era of American film-making the 70s. These are intelligent, well-crafted, not in your face, subtle movies about what/how things happen in real world, Not sci-fi, fantasy or gas explosion action.

• The Conversation (1974) - about espionage and surveilland
• The Parallax View (1974) - political assassinations & power of trans-national corps
• Three Days of Condor (1975) - how The Company operates and why you're never out until you are dead
• Network (1976) - not conspiracy per se, but underlines how manufacturing of consent through media works
• All the President's Men (1976) - although you should not believe this version of the Watergate story, it shows you how subterfuge works in political circles
• Winter Kills / - but a good look at the paranoid undercurrent after Watergate and JFK assassinations and how those can be played
• Blow Out (1981) - yes it's 80s, but still with 70s ethos... political assassination
• as a bonus piece, a French movie from 60s: Z (1959) - basically a telling of how NATOs Gladio secret forces operated and put the blame on others
• Seven Days in May (1964) yeah yeah, it's 60s, shoot me. This is basically about how the Deep State - CIA - Mafia -combo works to overthrow and assassinate elected leaders who don't play ball (cough JFK cough)
• Soylent Green (1973) - a crap as a movie, but it foresaw the whole industrial food corporation push for artificial food almost 50 years in advance
• Capricorn One (1977) - Never A Straight Answer and the space deceit
• The Boys from Brazil (1978) - the nazi connection (but of course with a Jewish POV)