Books with mysterious, isolated settings where the characters don’t have all the information and no one can get in or out?

This is real niche but I’m craving it. I have no idea how best to describe this, but I will try!

Examples (books and non books):

• Piranesi by Susanna Clarke
• Room by Emma Donoghue
• The Maze Runner by James Dashner
• Severance (the show)

Elements of the type of story/setting I’m looking for:
– the nature of the setting is unknown or in question
– the characters cannot leave or have never left, and don’t know what it is like outside of the setting
– there is very limited flow of information, material, or people in or out of the setting
– there are strict, weird rules (“no one goes through that door”, “if you try to do [thing], [bad thing] will happen”, etc)

What I DON’T want:
– entire isolated societies (City of Ember, Silo)
– short term isolation where everyone remembers their past, knows why they’re there, and knows what’s outside (regular spaceship or prison settings with no twist)
– books that mostly take place AFTER the isolation has been escaped (like in Kimmy Schmidt—adjusting to the real world after years in a bunker cult. I want the story to be IN the bunker cult, ya know?)

I especially love it when there is VERY limited scope (very few characters, very few objects, everyone knows everyone, every detail is important).

Down for any genre! Sci fi, horror, fantasy, mystery, thriller, whatever!

Anyone have good book suggestions? Thanks in advance!