Check out Raspberry Pi. Set up a streaming server, NAS, cloud storage. If you’re interested in media, make an installation. There’s tons of great projects available and I believe the best way to learn anything is by making something real, not just practicing random commands. Since it’s Linux based, you’ll learn a lot of practical uses of Linux and the power of being able to script Bash files.

https://www.raspberrypi.com/documentation/

Hope it helps.