Grand scale conspiracy horror?

I want something that deals with horror on a grand scale, that has nationwide/worldwide implications. A horrifyingly powerful and large conspiracy that makes the horror existing in the world itself, hopelessly.

Massive conspiracies, powerful cults, gnostic-esque worlds created by evil Gods. Ideally there’s a historic element - the origins of said threat being traceable to ancient times kind of thing.

Started the Tanis podcast and was incredibly intrigued by this mystery that spanned millennia and a powerful shadowy organisation ensuring its secrets remain secret just to find out it’s unanimously considered to be disappointing and convoluted, need something to scratch that itch left by the beginning episodes.