I'm a regular user but having been around for a while (and done some web dev) this course doesn't seem to go further (except in a few extensions) than my curren

I'm a regular user but having been around for a while (and done some web dev) this course doesn't seem to go further (except in a few extensions) than my current knowledge/experience. I've written bash scripts, configured Apache/Nginx, setup a mail server with spam filtering, used git to a basic level, all that kinda stuff ... what's the next step for a taste of what being a sysadmin is like?