“Ill made knight” ? Can you tell me more about that?
Andrzej Sapkowsky, the guy who write the Witcher, has written a series of historical novels set in Silesia, about the Hussite rebellion, (plus a lot of other supernatural stuff) which I liked so far, I think only one of them is translated into English so that’s the only one I read so far.
https://en.wikipedia.org/wiki/Hussite_Trilogy
I liked The Drawing of the Dark by Tim Powers. It also focuses on some supernatural stuff but it has Achille Marozzo in it at one point and I think he gets the HRE vibe pretty well.
https://en.wikipedia.org/wiki/The_Drawing_of_the_Dark
There is a series by this lady Dorothy Dunnet which is pretty good, set in Flanders but they make it up into the Baltic at one point.
https://en.wikipedia.org/wiki/The_House_of_Niccol%C3%B2
There is a rather obscure, old series of short stories, now in the public domain, by a Canadian guy named Robert Barr. I loved these and thought they really captured the ‘feel of the HRE with robber knights etc.
https://www.goodreads.com/book/show/14469447-the-strong-arm
Finally, there is a mysterious book of what you might call “off color” fairy tales, called “Waggish Tales of the Czechs”. It was written anonymously back in the 30s and nobody knows who wrote it. The stories are very similar to medieval Maeren and claim to originate in the bedroom of the famous Lady Barbara of Cilli, as she and her handmaidens passed the time one stormy night.
They are funny and do have an edge. So depends on your taste, but I thought they captured that medieval mindset (the tawdrier parts) very well. Some people might find them offensive though so fair warning.
https://www.abebooks.com/book-search/title/waggish-tales-czechs/
Those are a few off the top of my head anyway