I like microcontrollers. It is fun to see code do physical things. Plus, you can learn how simple computers work, which helps get an understanding of regular ones. Combine that with home automation, and you have an infinite time sink.

Most embedded systems programming software runs nicely on Linux (or sometimes even exclusively). PlatformIO, Arduino IDE, STM Cube, ESP-IDF… Obviously, something like a Raspberry Pi (and its alternatives) runs Linux itself.

Although, quite often, I find myself saying that since 90% of work and hobbies is either in a browser (including electron) or a shell anyways. Doesn’t really matter how the task bar / dock looks when all you do is run the same 10 programs