It’s a reference from an old comic

https://blogs.warwick.ac.uk/images/steverumsby/2004/09/20/1b2.JPG

As for Linux stuff grab something small and low powered (raspberry pi etc) and start installing some distros! The possibilities are really endless. Setup a network wide ad blocker, start your own IPTV server, you can setup a networked radio receiver, WireGuard for VPNs. Immerse yourself and figure out what you find interesting.

Here’s a nickel kid. Get yourself a better computer.

If you want to be a sysadmin learn Linux/Unix. Basic bash scripting might be useful down the line to help understand a bit of what’s going on under the hood.

IMHO networking would probably be a better secondary place to focus for a sysadmin track rather than OOP concepts, algorithms etc.