Failed documentarian roams the New Mexico mountain hunting a story until he stumbles onto a cult of women crucifying drug dealers to purge sin. He believes he’s found the story of a lifetime if he can live to tell it. Breaking Bad meets The Lottery.

It seems to me his initial?objective goal?should be?to find and document the cult -- he shouldn't just discover the women accidently. It doesn't make sense that he would be roaming a desolate, rugged?landscape hoping to stumble upon a story, any story.

Rather he's been lured into the wilderness by rumors of?the cult, and he thinks it would make a "killer"? subject for a documentary, one that will bring him critical acclaim and financial reward.

Well, it turns out to be a" killer"?subject -- but not in the way he had expected.

fwiw

Find another descriptor for your MC.
"Failed documentarian" could do with some tender loving care. Desperate documentarian perhaps? Lowly?

Agreed with Craig.

Best if you identify the specific goal he has to achieve and make that the focus of the logline.
As a result of discovering the cult what must he do? It's the answer to this question that will make the concept interesting.