So basically, you're touching on the greatest debate of German historiography history -- the Sonderweg thesis. In short, it rose out of the ashes of WWII as historians tried to wrestle the idea of how the heck this same country could start two of the deadliest wars in history in such a short succession of time. The conclusion was simple: Prussia and "Prussian militarism" and "Prussian values". This theory would spiral out of control into Sonderweg, "special path". This claims that the unique path to unification Germany took -- its late arrival to the party, its domination by Prussia (and thus by extension, its connection to 18th century Prussian militarism) domestically, and the rampant nationalism that was birthed in its numerous revolutions and wars leading to its unification -- uniquely set Germany on a 'special path' that made the Nazi brand of radical totalitarianism was inevitable.

Needless to say this is not taken very seriously any longer; it is most cogently deconstructed in Geoff Eley and David Blackbourn's work The Peculiarities of German History: Bourgeois Society and Politics in Nineteenth-Century Germany which is a work which was created explicitly to destroy the Sonderweg theory once and for all. Other good works are History of Germany, 1780-1918: The Long Nineteenth Century by Blackbourn again and William Carr's The Wars of German Unification for an overall look at the unification wars. Christohper Clark's Iron Kingdom: The Rise and Downfall of Prussia, 1600-1947 also deals rather in depth with Sonderweg and Prussia's involvement with the rise of Nazism. And my favorite work of all time, Ben Kiernan's Blood and Soil: A World History of Genocide and Extermination from Sparta to Darfur, rather expertly connects the pieces of the Nazi ideologies connection to militaristic fetishization of the past to justify their racial ideology.

I'm throwing a lot of books at you but this is literally a PhD level thesis level of discussion. I don't feel appropriately trained to really drop this level of analysis on you -- mainly because quite a few of those books are really high level academia that requires a strong background in the subject to really appreciate the nuance of. That's not to discourage you but to really let you know how deep of a subject this is. There is not necessarily a single answer, it's a giant debate within the history community and one that to this day is still having new works written about. However needless to say you're on the right track with your intuition -- but it requires further reading, more than I can give in good faith on an internet forum without completely butchering the nuance.