I bounced off The Green Man eventually because even though the text is extremely aware that the narrator/protagonist is a horrible little man making obvious mistakes through a veil of toxic masculinity and booze, the self-awareness still does not mean I wish to spend any time with him; but yes, it is indeed folk horror. The god/monster of the title is the relict of a sorcerer, who while dead is of course still hanging about. The threat is aimed at young girls and is sexual as well as physical. The protagonist is so toxic that not even his wife leaving him for his mistress could allow me to get through.

I note, however, that the book was filmed for television starring Albert Finney, which might, through charisma and acting chops, be tolerable. No notion of the availability of that version, but it's probably a better idea than reading the damn thing.