Looking for books that take place in the abstract/liminal and/or are lightly mystical/religious

Hello! I think the gold standard for the type of book I am looking for is Piranesi which is basically fully abstract, and liminal. Or maybe Einstein's Dreams. I just finished The Master and Margarita which did the trick, and G\*d Om*ns* kind of falls into the same bin, but both of those are slightly [...]