I'll spare you my comments on The Exorcist for when your soon to be published blasphemy hits Medium, but the point about Hereditary and God isn't necessarily a religious one. It's about counterpoint and what is dramatically satisfying. I think stories where protagonists are passive and nothing they do makes any difference to an outcome preordained by the gods (so to speak) are fundamentally unsatisfying. By contrast, a choice between good and evil (not necessarily God, per se), and the deliberate choosing of the later does make for a better bleak tale, in my not remotely humble opinion. :)