I like your notes on varying programming languages yet staying deep in one. I think this is turning into a consensus among the folks here who've been kindly offering advice.

And will consider this: "Maybe out of their many projects, they really took one or two all the way and polished, but most were fast, done and the lessons learned. ... They also stayed deep in the language and didn't rely much on frameworks & libraries."

This is also useful: "Code your own text editor Code your own interpreter". I find these types of things intrinsically motivating, thank you.