One of the genres of music I've recently begun binging on is Southern Gothic which is folksy, bluesy, and, oftentimes, full of religious imagery.
Something I believe would add to the atmosphere of either promotional material or a portion of the game Far Cry 5 itself is Ballad of A Prodigal Son by Lincoln Durham. Growing up with strong southern influences and a knowledge of backwoods rural America, I'd say that songs such as this can demonstrate, in a more sophisticated way than stadium country and a darker way than some folk music, the mood, presentation, and self-identification of either the religiosity or the sub-culture that the characters of Far Cry 5 are emulating.
https://www.youtube.com/watch?v=7OVZjqhRkqw
Thank you for reading, and I look forward to this game!