There is a post on a related topic by u/superplaner here https://www.reddit.com/r/AskHistorians/comments/1q0duo/was_the_prussian_army_as_disciplined_and_modern/, but speaks more to the qualities if the army itself than the role of the army in the state. It does however discuss the role of the sale of autonomy to the agricultural nobility in order to raise money for an army that would in turn subjugate said nobility, which laid the groundwork for the centrality of the Prussian army to the state.

What period are you talking about? I mostly know about Wilhelmine Germany up until the Great War (which was certainly a “Prussian” society), so if you’re enquiring on the preceding Prussian states of the 17th, 18th, and early 19th century I cannot help. Christopher Clark’s book “The Iron Kingdom” is wonderful, however, and you could also read up on it there. I would also suggest AJP Taylor’s “Course of German History” if you want to hear an account from someone who certainly believed so.