Agreed; you have to find a level that clicks for your students otherwise you're just throwing jargon at them. It's difficult to balance because knowing the subject well is required to teach it well, but knowing the subject well also means that your preferred abstractions are going to be too complicated [1].

A lot of people who want/need to understand the broad strokes of a database and how to query it effectively don't need to understand the deep, deep under-pinnings, and (unless you approach it cautiously) diving into it all will be actively counter-productive.

[1] https://xkcd.com/2501/