pi - number enthusiast uses his math themed mental illness to learn the name of god, gets in trouble with stock brokers and jews

the thing - a dog brings a special gift to an antarctic research expedition, the gift turns out to be inside everyone all along

the shining - a struggling author becomes caretaker of an isolated hotel, learns a bit about himself along the way

inception - yo dawg, I heard you like yo dawg, so I put a yo dawg in your dawg so you can yo dawg while you dawg

Get Out

Now that Chris and his girlfriend, Rose, have reached the meet-the-parents milestone of dating, she invites him for a weekend getaway upstate with her parents, Missy and Dean. At first, Chris reads the family's overly accommodating behaviour as nervous attempts to deal with their daughter's interracial relationship, but as the weekend progresses, a series of increasingly disturbing discoveries leads him to a truth that he never could have imagined.

Us

Accompanied by her husband, son and daughter, Adelaide Wilson returns to the beachfront home where she grew up as a child. Haunted by a traumatic experience from the past, Adelaide grows increasingly concerned that something bad is going to happen. Her worst fears soon become a reality when four masked strangers descend upon the house, forcing the Wilsons into a fight for survival. When the masks come off, the family is horrified to learn that each attacker takes the appearance of one of them.

Shutter Island

The implausible escape of a brilliant murderess brings U.S. Marshal Teddy Daniels (Leonardo DiCaprio) and his new partner (Mark Ruffalo) to Ashecliffe Hospital, a fortress-like insane asylum located on a remote, windswept island. The woman appears to have vanished from a locked room, and there are hints of terrible deeds committed within the hospital walls. As the investigation deepens, Teddy realizes he will have to confront his own dark fears if he hopes to make it off the island alive.

The Machinist

Trevor, an insomniac lathe operator who has not slept for months, experiences unusual occurrences at work and home. A strange man follows him everywhere, but no one else seems to notice him.

Hereditary

When the matriarch of the Graham family passes away, her daughter and grandchildren begin to unravel cryptic and increasingly terrifying secrets about their ancestry, trying to outrun the sinister fate they have inherited.

Midsommar

A couple travel to Sweden to visit their friend's rural hometown for its fabled midsummer festival, but what begins as an idyllic retreat quickly devolves into an increasingly violent and bizarre competition at the hands of a pagan cult.

The Lighthouse

Two lighthouse keepers try to maintain their sanity while living on a remote and mysterious New England island in the 1890s.

The Witch

In 1630 New England, panic and despair envelops a farmer, his wife and their children when youngest son Samuel suddenly vanishes. The family blames Thomasin, the oldest daughter who was watching the boy at the time of his disappearance. With suspicion and paranoia mounting, twin siblings Mercy and Jonas suspect Thomasin of witchcraft, testing the clan's faith, loyalty and love to one another.

In the movies mentioned above, most of them don't have the protagonist with the knowledge but it lies elsewhere.

It Follows, The Revenant, Suspiria (the old one or the remake), The Neon Demon, and The Revenant might also fit the bill.

The Game

• a birthday present for a brother goes sideways (drama)

The Man Who Knew Too Little

• a birthday present for a brother goes sideways (comedy)

Identity

• group of people stuck in a dangerous situation by a storm (drama)

Bad Times at the El Royale

• group of people stuck in a dangerous situation by a storm (drama)

Clue

• group of people stuck in a dangerous situation by a storm (comedy)

I feel like I most often see this genre refered to as "psychological thrillers". What you're describing sounds a little more specific than that, but it's where I would start. You also might like Enemy (2013). It's about a man who spots someone who appears to be his exact double in the background of a movie. Things start to become very strange when he tries to find out who he is.

Triangle (2009) - A group of friends out for an afternoon boat ride are hit by a sudden storm before coming across what appears to be a ghost ship. They go aboard looking for help or a way back to land before things go awry.

Coherence (2013) - A blackout during a dinner party causes even stranger phenomena once the power comes back on. The group of friends quickly lose each other's trust as problems begin to escalate.

Possessor (2020) - In the near future, a secret technology is developed that allows someone to take over another person's body. The story follows an assassin working for a secret organization as her grip on reality and her own life begin to slip, melding with the people whose bodies she takes over to carry out hits.

Dont Blink (2014) - Ten people at a remote cabin retreat notice one of them has gone missing when nobody was watching. Something supernatural begins to happen before they can figure out what's going on.

The Blair Witch Project (1999) - Not exactly what you're looking for, but it can scratch that itch. The legendary found footage film is about a documentary crew who venture into the woods in search of a local myth known as "the Blair Witch." They become lost and realize they aren't alone in the forest. The last ten minutes of the movie is among the best horror scenes of all time.

Mr. Jones (2013) - A young couple travel into the wilderness in search of a famous artist and sculptor known only by the alias "Mr. Jones." They plan on interviewing this anonymous person and making a documentary about his work. They discover Mr. Jones and his "sculptures" are the only things standing in the way of something sinister: an ancient evil hiding beneath the earth's surface.

Lovely Dark and Deep (2023) - A woman finally achieves her lifelong dream of becoming a park ranger at Arvores National Park. But this dream is rooted in childhood trauma and the new ranger's true motivations are revealed as she searches for answers in deep backcountry. It becomes apparent the rest of the staff are hiding a dark secret.

Ex Machina – A young programmer is selected to participate in a ground-breaking experiment in synthetic intelligence by evaluating the human qualities of a highly advanced humanoid A.I.

As an aside from suggestions, I think you are looking for "mindfuck movies" try looking that up instead.

Thinking along the lines of memento and 12 monkeys where the characters also suffer from memory loss or confusion along with the things they know or don't know there's Jacob's Ladder. It is a movie about a vietnam veteran who is apparently suffering from some disturbing PTSD, but obviously there's a twist or else I wouldn't bring it up. Oh apparently there's a remake, watch the one from 1990.

Not a movie but Paranoia Agent by Satoshi Kon (rip) is very good and I think will scratch that kind of itch.

Moon with Sam Rockwell might be kinda up that alley if you don't mind the Sci Fi setting and Kevin Spacey doing the voice of a robot

Mulholland Drive - Amnesia meets trying to make it in Hollywood.

If you like Primer, I bet you'd enjoy Timecrimes (2007). I'd say it fits the vibe you're describing.

characterized by something, a person who knows information (Be good or bad), and is in a situation isolated from the rest of the population, no one other than the protagonist or a very small group of people knows what is happening and what it implies

It's in Russian...

Stalker (1979)

A guide leads two men through an area known as the Zone to find a room that grants wishes.

Director: Andrei Tarkovsky

The Wikipedia summary is a bit more detailed.

The film tells the story of an expedition led by a figure known as the "Stalker" (Alexander Kaidanovsky), who guides his two clients — a melancholic writer (Anatoly Solonitsyn) and a professor (Nikolai Grinko) — through a hazardous wasteland to a mysterious restricted site known simply as the "Zone". [There's supposed to be a room there] which grants a person's innermost desires. The film combines elements of science fiction and fantasy with dramatic philosophical, and psychological themes.

Oldboy maybe? Dude was imprisoned in a hotel room for 15 years.

It’s not feature length, but 12 Monkeys is based on a short film by Chris Marker called Le Jetée which I highly recommend, along with all of Marker’s work, really. Marker deals a lot in documentary with a surrealist touch, and thoughtful narration. He’s a good old leftist too.

All the movies you mentioned are not just psychological, but are messed up temporally, so you might appreciate a newer movie called Time Addicts. Watched a bit of it and it was funny, dark, and wild, as a time traveling movie about meth should be.

The Manchurian Candidate is great (both versions are really, though I prefer the one from ‘62) as it deals with a character piecing together an experimentation plot involving hypnotism and proto mk ultra mind control. If I think of more when I’m rested i’ll jump back and comment again.

The Interview (1998)

The Interview is a 1998 Australian psychological thriller film from writer-director Craig Monahan, and is the first of three films directed by Monahan: The Interview, Healing, and a 2024 adaptation[1] of David Williamson's The Removalists. Almost the entire film takes place in a police interrogation room, with some short flashback sequences, and the cast consists primarily of three key actors—Hugo Weaving, Tony Martin, and Aaron Jeffery.[2]

Maybe "Beyond the Black Rainbow" could qualify?

Some of Satoshi Kons movies would fit. Especially Paranoia Agent. That's a 13 episode series but still:

"Seemingly unconnected citizens of Tokyo are targeted for bludgeoning by a boy with a golden baseball bat. As detectives try to link the victims, they discover that following the assaults, the victims' lives have improved in some way."

I think a lot of supernatural horror / fantasy fits this description, where the protagonist is experiencing something that nobody else believes. here's some of my favorites

A Nightmare on Elm Street - a group of teens are being murdered in their dreams, and none of the adults believe what is happening. 15 year-old Nancy is the only one to take the threat seriously, and after watching her friends die in their sleep one-by-one, she has to learn to rely on herself to fight back against Freddy Kreuger

Candyman - Helen Lyle, a graduate student researching urban legends, begins to lose her grip on reality when she encounters the Candyman, a mythical serial killer who haunts the Cabrini-Green housing project and is summoned by saying his name 5 times in a mirror

Pan's Labyrinth - a young girl in post-war Spain discovers an underground world of magical creatures and is challenged by a Faun to complete certain tasks in order to escape her fascist environment and ascend to her throne as an immortal princess of a faraway kingdom

Coraline - a girl with neglectful parents moves into a new house where she finds a portal to the "other" world where her "other" parents shower her with love and attention, but it turns out not to be the paradise she first imagined

The Nightmare Before Christmas - Jack Skellington, the Pumpkin King of Halloween Town, accidentally finds a door to Christmas Town, and upon returning home tries desperately to bring the joy of Christmas to his fellow townspeople who don't understand this strange new holiday

okay I just had to include that last one, you gotta admit it fits the description! this was a fun exercise

I regret to inform you this genre is called reddit

Hm. I think you have identified a plot/plot device rather than a genre really.

Memento I would put in a similar realm to Shutter Island (man is a detective in a mental asylum... or is he???!!) - that being psychological horror/mystery. You could add The Machinist to that (man cant sleep and goes nuts... or something - I don't really remember lol).

What I've noticed writing this is that those films are experiential narratives - you are essentially given the same disordered thinking as the protagonist.

12 Monkeys on the other hand is more science fictiony - a bit like Terry Gilliam's (12 Monkey's director) Brazil. (man becomes disillusioned in a surreal dystopia, everyone thinks he's mad). That's a great movie.

Now straddling experiential madness and Terry Gilliam is Fear And Loathing In Las Vegas, where you follow Hunter S Thompson's psychedelic Las Vegas drug binge from his perspective. It's not scary so much, but it might tickle your fancy.

You could also probably try any David Lynch film. Lost Highway. Mulholland Drive. Eraserhead.

otherwise...

Truman Show

The Game (Fincher)

Woman In The Dunes

They Live

Stalker (maybe)

Aguirre, Wrath Of God

Hard To Be A God (otherworldly scientist gets sent to a medieval planet, but is forbidden from altering their world)

White Noise (I didn't really like it, to be honest)

Bunny And The Bull (maybe)

The Hourglass Sanatorium (surrealist masterpiece I would say, a film like it will never be made again)

The Invitation (2015) seems to fit the bill.