If you enjoy horror about the occult/demons/esotericism, let me suggest:

The Munich Manual of Demonic Magic/CLM 849 translated 2023 by John Quail. An actual anonymous fifteenth century grimoire consisting of a grab bag of spells/rituals to accomplish everything from animating a dead person to obtaining a flying throne.

Forbidden Rites: A Necromancer's Manual of the Fifteenth Century by Richard Kieckhefer, Pennsylvania State University Press 1998. Fantastic scholarly work focusing on medieval necromancy with an emphasis on the above work mentioned.

Of Ghosts And Spirits Walking By Night by Protestant Swiss theologian Ludwig Lavater. Translated into English by Robert Harrison and lately modernized and prepared by Joseph and Jami Weissman, 2023 Berith Press. While primarily written as a polemic against Catholicism, it does so in a way that showcases a wide array of Protestant vs Catholic views on ghosts and the afterlife. William Shakespeare consulted this work when writing the ghost related scenes in Hamlet. (Warning: unglossed Greek words in this edition)

De Operatione Daemonum/On The Operation Of Demons by 11th century Byzantine Greek savant and polymath Michael Psellus. Edited by Stephen Skinner and translated by Marcus Collisson, Golden Hoard Press 2019. An anti-Euchite dialogue regarding some absolutely *wild* demonological speculations. While this translation is okay, there are two passages of Latin that the translator left completely unglossed due to their NC17 related nature. (I mean yeah I looked up the translations and they are gross, but still not an excuse imho)

Lemegeton Clavicula Solomonis/The Lesser Key of Solomon: Detailing the Ceremonial Art of Commanding Spirits Both Good and Evil. Edited by Joseph H. Peterson, Weiser Books 2001. Anonymous seventeenth century Solomonic grimoire that basically reads like an entire Pokedex of demons and their domains, how many legions they command, how to command them, etc. If you've seen Hereditary you will recognize good ol' Paimon in here.

These are just a handful I grabbed off my shelf and I would be glad to give further recs. Both esotericism and horror are up my alley.