As in, this is super mega nerd shit. Unless you can relate things you're reading to things you've read before, it won't make too much sense to you. But if you're constructing a theory of the book's universe and story as you read, it's downright addictive.
I don't know where to find more books like those but I really, really want to.
Regarding recommendations similar to Ra, it's not exactly the same thing, but https://unsongbook.com/ is fantastic and has a similar flavor I think.
(also, I liked Antimemetics, but not Ra, so I will just say I think unsong is leaps and bounds better than Ra)
The religious references on the actual website (and lack of much real explanation) made it very difficult for me to give it a chance, but I looked it up a bit and it seems like there is more to it than that, so maybe I'll give it a try.
edit: reading the first chapter definitely changed my first impression. It definitely has many similarities to qntm's writing. I will certainly be reading more...
“STOP TRYING TO UNDERSTAND THE WILL OF GOD,” said Uriel. “IT NEVER HELPS.” --the archangel Uriel
> "Are you all right?" Sohu finally asked.
> "I WAS TRYING TO WIGGLE MY EARS."
> Sohu wiggled her ears again.
> "YOU ARE VERY INTERESTING."
> "So will you teach me the kabbalah?"
> "NO."
it's so cute!! I love this
also, I love how many references it makes to actual programming; it's always hilarious to see Uriel explaining code bugs in reality.