As sad as it is, the more you take care of content warnings the higher the expectations people have from you and the bigger the fallout is when someone finds something to complain which is out of your hands as you can't know every little thing people might find objectionable now or in the future.The more and more I think about it, the more I'm leaning on just putting a brief label at the beginning, on the cover, and than a paragraph about the importance of session zero on how it relates to some of the dark lore as presented. And leaving each individual creature entry unlabeled.
Paizo currently suffers from that. Any other company would have gotten away with the current issues much more easily and things would have been forgotten already.