There Is No Antimemetics Division (2018)

If you like this kind of thing, the rest of qntm's work is definitely worth checking out - as evidenced already in several comments. Another good pointer to follow is to Unsong and Scott Alexander's other fiction (all shorts, spread through his old blog Slate Star Codex and new blog Astral Codex Ten).

Both of those were already mentioned, so let me drop a recommendation for something new - Worm, the first (and absolutely massive) book in Wildbow's Parahumans series. Iirc it's longer than all 5 published ASOIAF novels combined, so it's a big commitment, but that length moves through a ton of different arcs. It's centered around a "superheroes" kind of scenario with a level of analysis and thought that'll tickle the fancy of certain kinds of nerds. The main character's power is to control bugs - and it's a lot of fun to see the author make that seemingly lame power into something incredibly useful and lethal. It's just a fun read overall, lots of room to nerd out about it. I haven't read the sequel yet, but I've read good things.

Also, though they're more mainstream, Greg Egan and Ted Chiang are some of the best spec-fic / sci-fi authors I know of, and do a similarly great job of breaking down interesting concepts into compelling stories.

If you are into massive stories. Have a look at The Wandering Inn. It's a bit longish.

Is it longer than The Loud House: Revamped, currently at 2328 chapters and over 16 million words?

I mean I just glanced at it and I'm sure it's a troll, with passages like

> Flying over the western Pacific Ocean in the world of the 2022 movie The Mermaid Monster was Nico, The Ripping Friends, Ellie Singh, Evelyn Burmingham, Jen Tennyson, Eddy, Yugi, Tea, Jaden, Jesse Anderson, Allenby Beardsley Knudson, The Hernandez Sisters, Yost Magma, Rin Nohara, Woz, Bai Tza, Sabrina Lorelai the Despair from The Dark Gene-Slammer, Albedo, The 1983 D&D Gang, Donbrothers, Irina Krafla the Granity Gene-slammer, Kora Lexxington, Olivia Houou, Nataša Marečková, Nalanie Nanthavong The Vorash Gene-Slammer, Brynja, Sissi Delmas, Anna Anyanova the Destiny HERO Dark Angel Gene-slammer, Daring Do, Lizzie Strong the Great Blue Windrunner Gene-slammer, Emam Reynolds the Living Tsunami Gene-slammer, Wendy Sapphira, Reggie Hjorleifsstræti the Five Headed Dragon Gene-Slammer, Qin, Miku Yuuki, Princess Anita, Granity, Rei Miyamoto, Saya Tekagi, Saeko Busujima, Shizuka Marimoto, Kamen Rider (1971), Hibiki Riders, Agito Riders, Kabuto Riders, Den-O, Kiva, Decade, W, OOO, Fourze, Wizard Riders, Blade Riders, Faiz Riders, Gaim Riders, Drive Riders, Ghost Riders, Ex-Aid Riders, Build Riders, Zi-O Riders, Zero-One Riders, Saber Riders, Dragon Knight Riders, Granity, Samurai Jack, Ashi and her sisters, Changeman, Jetman, Dairangers, Zenkaigers, Chloe Bourgeois, Shanan, Rita Loud, The Goths of Darkness, Zarya Moonwolf, Applejack, Apple Bloom, Twilight Sparkle & Friends, Sunny Starscout, Izzy Moonbow, Hitch Trailblazer, Pipp Petals, Zipp Storm, Misty Brightdawn, Wallflower Blush, Alice Kingsleigh, Rachel Stavenport, Kate Lloyd, Carol Pusateri, Hailey Helios, Kia, Jenna, Lina, May, Maria, Danica Metrois, Kaalia of The Vast, Varie, Sakura Valencia, Xenia the Xerneas, Bhavna Radhakrishnan the Xerneas Gene-Slammer, Bridgette, Eli, me, Sakura Knudson, Arrietty, Aylene Carter, Gabrielle, Littlefoot and friends, Fu, Nicole Knudson, Spiderman and his counterparts, Kaina Tsutsumi, Nick Logan, Sh'Lainn Blaze, Camie, Kaoruku Awata, Himiko, Ibara, Toru, Sirius, Tsuyu, Ochaco, Luz, Amity, Gus, Willow, Hunter, Felicia Wittebane, Carly Atlas, Misty Tredwell, Zuria, Tony Jones, Edyn, Strag, Momo, Girl Jordan, Leeli, Sora Phaaze, Venus, Earth, Vinyl Scratch, Airazor, Rhinox, Cheetor, Rattrap, Tigatron, Janeen Aran, Lincoln, Leni, Laney, Lana, Lola, Lisa and Lily along with Misty Brightdawn's team with Roxas, Aeleus, Laurium, Elena and Dilan as well as Pintar, Yokubarido, Evil Earth Minions, Tristesse (Animaniacs), Francis X. Bushlad, and Castaways (Looney Tunes) and we were heading to a small Chinese Village for an amazing rescue.

and

> Suddenly, Kelly Strahand's trident and all the greatswords and swords that she'd gotten began to merge together, and they were surrounded by a kaleidoscope of ocean blue energy, stars, water, ocean waves, lightning, sea creatures, mermaids, phoenixes, and angels, and when it emerged, it was transformed into Kelly Strahand's True Cosmic Eternal Harmony Oceanic Water Maelstrom Mermaid Light Side Legend Protector and Dark Side Legend Slayer Phoenix God Angel Greatsword of True Cosmic Eternal Harmony Oceanic Water Maelstrom Mermaid Light Side Legend Protector and Dark Side Legend Slayer Phoenix God Angel Justice, it's a brand-new massive greatsword with embedded blue gems and a mermaid etched on the 8'0" massive, wide, double-edged gold blade, large gold phoenix heads with ocean blue gems for eyes for the crossguard, large white angel faces built into both sides of the hilt and large ocean blue gems embedded in their foreheads and surrounding the white angel faces are the Elements of Harmony and the Unity Stones on top of the Element of the Magic of Friendship, longer midnight black handle, four large gold raven heads with ocean blue gems for eyes and on the bottom of the large gold phoenix heads is a large gold phoenix head with ocean blue gems for eyes and ocean blue gem in its mouth for the pommel, Carly Almaden has on her brand-new large gold Bracers of The Champions of The Universe with large ocean blue gems on her arms and Dragon Ball Bracelet and wrist computer and Omnitrix on her left Bracer, her large gold Belt of Elemental Bravery with a gold mermaid's head with ocean blue gems for eyes and ocean blue gem in its mouth for the belt buckle on her waist, large rainbow-colored leather and gold metal bound Elemental Spellbook of Harmonious Justice, Eternal Harmony, and Equestrian Peace and Talisman Cards of The Universe and Talisman Cards of Eternal Elemental Harmony on her right hip and Eater of Sins revolver holstered on her left hip. There's an ocean blue kanji with water drops and lightning bolts in between the kanji below the mermaid that said, "Kelly Strahand, Defender of The Mermaids of The Light Side of The Legend, Powerful Force of Good, Thrasher of The Bad Guys, Master of Water and Lightning, Slayer of The Mermaids of The Dark Side of The Legend, True Immortal and Omnipotent Powerful Warrior of The Universe, Loving Guardian Angel and Future Wife of James Dean Knudson, Amazing Member of Team Loud Phoenix Storm, Brave Warrior of The Cosmos, Protector, Defender, and Savior of The Universe, Multiverse, and Beyond, Ambassador and Beacon of Hope to The Universe, Master of The Powers of Friendship and The Elements, Master of The Fury of Celestial Xelnaga, Master of The Black Gates, Ultimate Force of Ultimate Good, True Goddess of Truth, Justice, Love, Compassion, Hope, Forgiveness, Valor, Virtue, Determination, Loyalty, Honesty, Generosity, Kindness, Selflessness, Courage, and Trust, Destroyer and Slayer of Evil, Deranged, Murderous, Ruthless, and Sadistic Bastards, Amazing and Powerful Student of Amazing and Powerful Teachers, True Immortal Hero, and Master of Stars, Water, Water Magic, Lightning, Sea Creatures, Mermaids, Phoenixes, and Angels"