Start with high-confidence war fiction books, then narrow by subgenre or adjacent topics.
HMS Ulysses
Unknown author
Warhost of Vastmark
Grand Conspiracy: Second Book of the Alliance of Light
The Iron King
The Centurions
Jean Larteguy, Paul Woodson
For Whom the Bell Tolls
Ernest Hemingway, Campbell Scott
Britannia (eagles of the Empire 14)
Simon Scarrow, Jonathan Keeble
Island Ablaze and Other Stories
Ruth Barraclough, Jae-Yong Kim
Tales of Soldiers and Civilians
Ambrose Bierce
Under Fire
Henri Barbusse
All Quiet on the Western Front
Erich Maria Remarque, A. W. Wheen
Tales of Three Hemispheres
Lord Dunsany
War of the Worlds
H.G. Wells