Honestly, throw a couple services running on ubuntu servers on the proxmox machine. It’s not the same as book learning, but it does help a lot with the basics and patchy knowledge I found. Not saying I’m an expert or anything, but I do know a lot more about managing Linux servers now than I did 5 years ago from running 15 of them on Proxmox
Hey that’s my old CPU which I just retired from my old pc. If it wasn’t somewhat set aside for a pc for my SO it would be my new video encoder. The two servers I do have running do have some issues. The proxmox machine has a dead RAM slot and several dead fans or dead fan connectors. (Enough run to keep it cool at least). The Truenas box keeps showing an error with the second PSU and the vga out does not work (Either on front or back). Both work well enough for me.
For anyone who is interested on the software I’m running through my proxmox server -
I have an email server but it is not my main email account. I’m purely only using it to learn and to have email notifications sent out from a few services. I do not trust myself or my setup enough to have my main email account hosted on it