Glen Cook has an absolutely fantastic series called The Black Company where the entire series is framed as being the recorded annals of a mercenary company, wit

Glen Cook has an absolutely fantastic series called The Black Company where the entire series is framed as being the recorded annals of a mercenary company, with who is writing them switching occasionally between books to different characters, which let's you see the narrating character who usually writes them from a different, and sometimes less flattering, perspective. In any case, unreliable narration is obviously a big of the series, and the concept that just because something is written down doesn't mean it happened that way is pretty central, and I think it's outright brought up by the narrator at least a few times, and reading between the lines/making inferences that don't line up exactly with what is recorded is pretty much necessary to understanding the plot of the series sometimes. Cook also served for 10 years, not sure if he ever saw active combat but the series is constantly praised by veterans for it's accurate portrayal of what life in the military actually feels like.