As a complete beginner, what can I do with a raspberry pi 4b?

I'm basically completely new to networking and currently setting up a NAS. I have this raspberry pi 4b that I got but now can't think of a use case for it...

Any ideas of something that is very useful to host or have running on the pi4b?

Edit: I'm a complete beginner, and will use trunas on another server with jellyfin so my raspberry pi gets blown raspberries atm 👎