Radiate_Wishbone_540

I'm almost ready to build my first DIY PC which will be used as a home NAS/server. My primary aim is media storage and playback (mostly music, only the occasional movie).

While I'm not quite done deciding between TrueNas and UnRaid (and Proxmox?), something I see discussed in all three setups is the use of VM's, or virtualization.

While I understand the concept of a VM, I don't understand how this might figure into what I'm doing.

To take my primary aim of storing and streaming music, possibly with the use of Jellyfin or Plex, how would a VM come into play, if at all? Can I simply install the OS of my choice and the install software like Jellyfin or Plex, or is this where VMs become important somehow?

Explanations, tips and resources shared are appreciated.

Making my first DIY NAS build. I was given an Intel i5-9500T for free, so I'm basing the build around that.

My use-case is pretty minimal, mostly music storage plus some light use of Plex.

A nice-to-have on the mobo would be 6 SATA 6gb/s ports, but if it doesn't but at least has pcie expansion, that's fine.

I want to go for power efficiency. Which boards tend to be better at this? B360, Z370 or Z390? And what am I missing/not getting right in my understanding of this (this is Reddit after all!).

Thanks