General advice not necessarily optimized for hirability:

First thing you do: Get another one of what you're already getting.

That way you can actually run "production" and host stuff while you can experiment and play around fearlessly without breaking prod. You'll also have a spare on hand in case of hardware failure etc.

Second, do at least basic separation of networking right away. Get a $10 switch and separate subnet instead of piggybacking on your home LAN.

Then, get comfortable with virtualization (qemu+kvm) and figure out a way to automate image your image builds and deployments.

Automate backups early. Start simple and iterate over time.