Do you want to know how it works internally or how you can administer it more effectively? The two are very different. I was always more interested in the former than the latter and at one point read through Linux kernel 0.1 source code. I want to know how a kernel and a file system works but I can’t be bothered with configurations and shell scripts. The good thing about Linux whatever you want, the resources and the source are available.
Good luck.
Not just Unix-like but actually ancestrally Unix as well as being certified as Unix