You don’t need to delve into networking too heavily at first. I recommend ProxMox as the most beginner friendly platform. It’s open source and based on Debian 12 underneath. That means that updates won’t hit you until they’ve been run in the wild for a while. This is what you want for a server.

It has a free backup server you can use to take automatic backups, and it can run virtual machines, lxc containers, and docker can be installed on an lxc or vm and you’re golden. If you install docker bare metal you limit yourself to docker.

The new SDN functionality also lets you make self-contained networks that isolate your vms. Couple with this opnsense eventually, and you can make a nice public setup and not worry too much about east west security.