It’s diverges from reality quite a bit for sure. Lt Dike wasn’t actually a coward at Foy. He was shot which is why Spiers replaced him. Everyone disliked Nixon except winters. Moose hyliger was shot because harry welsh was drunk on duty. Far as I can tell Spiers’ depiction is the closest to reality. He did shoot the prisoners, he did shoot sgt carington, and he did run through enemy lines at foy. The whole story is filtered through the biased and aged minds of winters, Lipton, guarnere and Heffron. Their distaste for some others taints their recollection and thus the book and show
It is still a fantastic show, I’d argue almost perfect from a structure point of view.