Canticle for Leibowitz is a classic piece of sci-fi that spends most of its time in future medievalism but it kind of cheats in that it’s both post-apocalypse and society rebuilds its tech base by the end.

Other than that it sounds like you want future fiction without all that pesky science.

I’ve wondered about a sort of fantasy story with all the hallmarks of science-fiction. Maybe a wizard grapples with the ethical problems that a new spell would unleash if he were to use it. He could end famine for all time for his people, but maybe it makes every other land in the surrounding area inhospitable to life. Or something along those lines where a new “tech” will cause a major disruption with moral/ethical dilemmas, it’s just that the “tech” is some sort of magical device or spell, something very fantasy-based. Everything would take place in a medieval era, nothing high-tech at all, but the whole thing is structured like a sci-fi story. After all, medieval tech is still “high-tech” depending on your temporal point of view.

Anathem by Neal Stephenson

Stories of Your Life and Others by Ted Chiang

The Caves of Steel by Isaac Asimov

Cat’s Cradle by Kurt Vonnegut, Jr.

The Godmakers by Frank Herbert

Self-Reference ENGINE by Toh EnJoe

*Bonus: Low (comic series) from Image

Try searching for authors who describe their work as “Speculative fiction” - that’s the way most of them don’t admit to writing low-brow schlock like sci-fi.

Also near future sci-fi tends to be a bit lighter on the “magical machine” plot tropes. Climate fiction might be worth looking into too, most of the near future books exploring possible global warming consequences aren’t all hopped up on magical technological advances.

Edit: also check out various books described as literary speculative fiction. Authors who want the intellectual cred of being a literary writer tend to land in the speculative fiction genre more often than not.

The Dune universe lacks computers, which is why spice is so valuable - does that count? Still has plenty of machines, but they aren’t the story

It’s called Dune

There’s plenty of star trek episodes that are more about philosophical and societal questions than tech.

The bicentennial man by Isaac Asimov comes to mind. Which is about a robot, but in essence it’s about the philosophical question what it means to be human.

There’s Ubik by Philip K Dick, which is about about tech, when you get down to it, but in a very unique and un-tech like way.

Flowers for Algernon by Daniel Keys is not about tech, but the chronicles of a brain surgery patient that became extremely smart.

Hyperion by Dan Simmons is basically just “The Canterbury Tales” in space.

There’s plenty more stories that are not really about tech. You could try searching for dystopia themes, like “Maze runner” or “the hunger games” or “I am legend” or “wayward pines”

Any sufficiently advanced technology is indistinguishable for magic

Dune.

What are some examples of things you don’t like? That’s really necessary to give examples. Science fiction usually has technology in some form or another. Sometimes it’s the focus of the story (eg The Last Question or Permutation City). Sometimes it’s a tool for the story (eg The Expanse or Neuromancer_). Other times it’s set dressing like magic in fantasy (eg Dune or Book of the New Sun). Outside of hard SF and beyond Golden Age SF you run into more “tech as device or background.”

Children of Men would be a sci-fi without any significant technological improvements. Ender’s Game does have the Ansible, but it’s more a plot device than anything.

Probably not exactly matching your meaning, but in a round about way, Dune, post Machine Crusade –

It’s maybe not as evident without reading the series–which definitely isn’t a negative comment! I’ve enjoyed (almost) every bit of the truly shocking amount of Dune I’ve put myself through since the very early '90s, haha.

I’m, uh, mildly obsessive as well as critical of the SF I stand by, (just for myself personally!–everyone should like whatever they like!) but Frank Herbert, entirely, still remains in my top 2 favorite authors. You may enjoy all the books as a whole, if you’re looking for something less about ‘the machine’ itself, but how humans diverge from it and without it, but it’s…a lot, lol. And…well, I won’t spoil things. I just remembered it might negate my entire point. Oh, no. (ʘ‿ʘ)

Anyway! Regardless!

If you do ever get into full-ass Dune–and I’d recommend this “tip” to literally anyone–I’d definitely suggest audio books for the early works of Brian Herbert and Kevin J Anderson. They took a bit to get into their groove from informational to actually entertaining. The lore is honestly fantastic, beautifully done, but physically reading their earlier Dune stuff can be textbook without diagram tedious. Love 'em both for the work, but shiiiiiiiiite.

Science fiction is in it’s essence the exploration of a situation when all the confounding factors have been magicked/scienced away.

Not uncommonly it explores the requirements of the technical solution, what would the machine need to do for this to work out? And/or What happens if it doesn’t?

Take for example “Do androids dream of electric sheep” by Philip K Dick, it’s about finding androids advanced enough not to know they’re artificial and how to identify and relate to them when the only diagnostic is slow, clumsy, and suspect. It’s more an exploration of what makes a person than it’s around the marvels of The Machine™.

During the 1900s the vehicle for science to magick with had been machines, computers and AI. Remember that space travel, fission power, psychology, modern medicine were all new, hope inducing breakthroughs just this same period.

There’s also the issue that the definition of the genre came after it becoming large enough to matter. The edges between scifi, punk/cyberpunk, speculative fiction, isekai and even to fantasy are all made after the fact, meaning modern machines go into scifi, old machines go into steam-/diesel-/etc-punk. The main difference between Science, Magick, and Eldritch horror is how detailed the mechanics of the solution are described, and speak to different people.

But on the topic of the story not being centered around a machine: try the Hyperion series by Dan Simmons.

Or go the entirely other way with Ring World by Larry Niven. There’s plenty of machines-did-it in the fringes, but the central theme is to figure out what would be needed for a Ring World to exist, what would happen on it, and how would it be managed. It’s an exploration of physics more than anything - more “what is the machine” than “machines-did-it”.

And the Foundation series (Asimov) famously explore the premise “what if sociology works”, and the other details solved by throwing machines at them.

You also have The Culture (Iain Banks) series that center on/around post-scarcity society and explore that.

Check out Terminal World by Alastair Reynolds

There’s plenty of science fiction without technology playing a significant role.

Robert Silverberg’s Dying Inside was the first that came to mind; Asimov’s The Gods Themselves or Nightfall might be other examples; Olaf Stapledon’s Sirius; Clarke’s Childhood’s End has (alien) tech, but it mostly focuses on the psychological and societal effects of the contact with aliens, as does Ted Chiang’s Story of Your Life (and some of the other stories collected in the same volume, Stories of Your Life and Others); Philip K. Dick’s The Man in the High Castle, Kurt Vonnegut’s Slaughterhouse-Five… lots of great science fiction works focus on aspects other than technology.