For an example of QML and JS only Local storage you could look at:
Startpage doing retrieval and feeding a ListModel:
The Javascript which also initializes if the DB is missing:
A search page which writes locations that are selected to the DB:
I studied the meteoswiss weather app to glean most of what I learned and cribbed code, of course.
There’s also Positioning, json api usage and custom Font usage, so a bit of stuff that might be useful.