I think this is the kind of content I need. One that presents a problem and allows me to figure out a solution.

Can you recommend any other content like that?

Good question. I guess my answer is not really. I'm not sure why I haven't sought out more of this kind of thing.

Still, a couple of random things I can think of:

The Spatialite Cookbook is no longer maintained, but I think still useful. That's structured as a sequence of fun exercises: http://www.gaia-gis.it/gaia-sins/spatialite-cookbook/index.h...

I also enjoyed Peter Norvig's Design of Computer Programs online course: https://www.udacity.com/course/design-of-computer-programs--...

projecteuler.net?