Did you ever read Nazi Oaks? By Mark Musser? He’s from your area. He documents a green movement in Germany that fascinatingly lead to the Holocaust as an oft missed major contribution to Nazi ideologyI find documentaries to be my favorites. This one may not actually be considered a documentary, per se, but will surely be a fascinating film to watch.
I watch a lot of documentaries on WWII. I will admit that the entire Nazi Germany things fascinates me in many ways. What drives a man (Hitler) to such hatred? How could an entire nation follow that ideology? How can human beings, in general, treat each other the way they did? I watch with a morbid fascination, and try to get a sense of some of the possible answers.
As you stated, WWI is a whole 'nuther thing. What little I have read or watched regarding it is equally fascinating, and I can see myself looking into it more.