Translation from English is unsuitable since there are thousands of words and many wouldn't be 5 letters once translated. See "answers.txt" and "full.txt"
https://github.com/bbbbbr/gb-wordyl/tree/main/compress
Better to find an already compiled German word list (perhaps even Word list) and then filter that to 5 letter words (and as you suggest, exclude ones with special chars is sufficient).
Then split into a set of most common words (answer list) and remaining words. Sometimes that sorting is already available somewhere. And perhaps look through answer list to remove the more "offensive" words.