Code Crafters, and other project-based tutorials

The projects here seem to be short, well-defined and decent way to familiarize with internals of a few technologies (such as Redis, Docker etc.)
- https://app.codecrafters.io/tracks
This repo also seems to be good: https://github.com/codecrafters-io/build-your-own-x. ~~For e.g., write and OS in Rust~~ - complicated and likely not useful for me.