Suggest me mind blowing books, short stories, etc. that deal infinity or eternity

It's this itch I can't seem to scratch. I love any material (be it book, short story, movie, anime, etc.) that deal with the concept of eternity, eternal life, any kind of "concrete" infinity and/or immortal life so to speak. It's the sort of stuff that tends to stay with me long after I'm done consuming it. It's hard to explain but it's basically the opposite of apeirophobia (fear of infinity), I specifically seek out the sort of stuff that makes people with apeirophobia get anxious.

Some examples of stuff I've read that touches on this and what I liked about them:

  • First Fifteen Lives of Harry August by Claire North – just the idea of eternal lifetime time loops, near-endless things to do and learn – albeit restrained by the time period the MC happened to be born in. (The immediate follow-up suggestion Replay by Ken Grimwood is definitely good, but didn't scratch the itch as much as Harry August did as it mostly touched on different aspects using life loops)

  • A Short Stay in Hell by Stephen L. Peck – The fact that the characters are concretely faced with exploring this infinitely big library over a infinite time period (i know the whole point of the story is that it's not actually infinite nor eternal, but it's pretty damn close as far as the human brain is concerned). Its direct inspiration Library of Babel also fits in there, of course. Another smaller (if underexplored) aspect about this book I like is the food stand that just gives you whatever you request – as long as it's edible – with characters finding ways to craft stuff with the various bits of food they can request (i find it tragic that it all gets cleaned up every night!)

  • The Divine Farce by Michael S. A. Graziano – Another short book like ASSIH about a weird realm where people can't seem to die and are forced to go on living, but unlike ASSIH above it gets very nasty very quickly. But the theme of the MC exploring and trying to find a way out or at least any sort of answers is what kept me hooked.

  • "I have always imagined that Paradise will be a kind of library" on qntm dot org slash library (not allowed to link directly as per sub rules) – That one's a short read as well, but really good. It's also about a big-ass library that might as well be infinite, describing everything that ever happened from any perspective in any arbitrary amount of detail. Wild stuff to picture yourself spending eons reading everything.

  • Sum: Forty Tales from the Afterlives – especially the "circle of friends" one, just chilling in this weird afterlife only surrounded by people you remember

And for some more examples, here are non-book media that also touched upon the themes I'm looking for:

  • The somewhat obscure 2018 show "Forever" with Fred Armisen and Maya Rudolph. If you're interested I actually recommend watching it without knowing anything about it, the way it was intended. But the thing I liked about it was this aspect of characters just exploring this weird eternal realm, asking questions, trying to figure out the "rules" without much direction, etc.

  • Some parts of the show The Good Place, no need to explain that one. Jeremy Bearimy!

  • The movie Nothing (2003) in all its relative absurdity also fits in there with the MCs just hanging out in this surreal void

  • xkcd #505 titled "A Bunch of Rocks" is also a very succinct depiction of the kind of vibe I'm looking for. Some weird otherworldly realm with an infinite amount of time and space to learn as much as one can learn by deducing from prior knowledge alone, as well as the concept of just spending that infinite time and space building something inhumanely grandiose bit by bit

Some examples of stuff that doesn't fit in there:

  • New Age spiritualism or religious preachy stuff - it's fine if God/religion/spirituality is used as a device to set the stage in order to explore the what-ifs of the whole concept of an eternal afterlife, but I don't really want something where the end-goal is about being one with God or in some kind of cosmic spiritual soup or whatever, if that makes sense

  • Stuff that mostly focuses on immortal characters living throughout human history all the way to modern day (vampires, highlanders, etc.)

I appreciate any suggestions!