I know this is a discipline where like half the professors still unironically recommend Fehrenbach, so "left wing military history" may be an oxymoron. But thoughts on left leaning military history books about the 20th century ?

Closest I've read is maybe The Blitzkrieg Legend by Karl-Heinz Frieser, which rips apart all the wehraboo bullshit and argues that the German army that conquered France was an ill-equipped bunch of incompetents who won in the Ardennes because of some well-timed cloudy days and some officers who went across the wrong bridge at the right time. But the author is a Bundeswehr colonel, so that's not exactly "of the left."