Ask HN: What is a good small Linux for education

I'm seeking advice on which Linux distribution to choose for educational purposes. To provide some context: I have been programming for the last 12 years. I understand how transistors, processors, and microcontrollers work. I can write low-level firmware in C and also use Linux as a tool for my work. However, my knowledge gap lies in understanding how the Linux OS operates. At the same time, I'm not yet prepared to invest time in reading theoretical books on operating systems or delving into the Linux source code.

Instead, I desire the most minimal Linux setup that I can experiment with. My minimal goal: I aim to configure a Linux system with networking capabilities and run a service in such a manner that I have control and understanding of all the components involved and can ensure its security.