Knowledge for its own sake is exactly what Judaism is about
That ONLY applies to study of the Jewish texts. It does NOT apply to secular knowledge, such as science, culture, literature, and law to take some of your examples above.
you need a doctor, do you think that he or she should not have pursued his or her knowledge for its own sake? The best ones do, you know.
I don’t believe that for a moment. They studied the material for the sake of practice, not for the sake of knowledge alone.
I know a few people who did graduate work on the study of Piyyutim–by crawling into the material found in the Cairo Geniza and published previously forgotten Piyyutim and Kedusha’ot.
The Cairo Geniza material is unreliable and unauthoritative.