So far as I can tell, it is uncommon to come across educational content in the field of software development which provides an appropriate mixture of theoretical and practical information. If I was to guess why, I assume it is because individuals who focus on theory tend to get into teaching, and individuals who focus on practical information tend to get paid to solve specific problems, using specific languages and tools.

https://www.smashingmagazine.com/2019/11/guide-oop-inheritance-interfaces-abstract-classes/