Honestly for a German principality Prussia was pretty normal, if surprisingly successful. Take Reuss elder line, which was so conservative it had to be forced by Prussia at gunpoint to adopt any constitution at all, opposed any change (e.g. the BGB), did grudgingly found its first high school in the 1880s and was still using a 18th century administrative organization until 1918.Prussia if you had created some thing like it in fiction people would tell you it's unrealistic also Venice
Or Mecklenburg, where the estates held onto their 1523 constitution until 1918. It was maybe the only German state were the ruling princes actively tried to force a modern constitution onto their people and failed due to local opposition multiple times since 1848. The last prince considered a defacto coup to finally get one. Despite this the state was otherwise fairly modern.