War movies that convey the horrors of war

My buddy at work is a movie guy, and he LOVES horror/thriller/suspense movies. His favorites are Hereditary, Martyrs (The French Version), Banshee Chapter, Adam Chaplin, and Evil Dead (2013). I believe he watches 2-5 new movies a week. I'm not a movie guy, I watch maybe one or two movies a year, and they're almost always war movies (1917, Private Ryan, etc).

I want to be able to connect with and share a movie with my friend. I want to find a war movie that really conveys the horror and nerves of war, something that really makes the hair stand up on your neck. I've never seen any of his favorite films listed, since I don't really like straight up horror movies, so I am unfamiliar with the specific vibes his selections provide. I believe there must be some kind of film that would have the "realistic" wartime dread feeling combined with the edge-of-the-seat thrill a horror/suspense thriller provides. The horrors of real-life war makes Hollywood's tricks seem childish in comparison, and there must be a movie that captures this, right?

I love history, and I've read a lot of books about the feelings men have in war and combat, and I believe that if a film could capture this feeling, it could easily rival the vibes of the horror franchise. Does anyone have any good suggestions? Thanks for your input!