Your asrock option should be good, you are concerned about power draw but the manual asks for 90w adaptor with 2 HDDs.

The Odroid has a more specific ask

– DC 19V/7A power adapter is recommended if you use more than one 3.5” SATA HDDs together

Your 90w may be underpowered in either case hard to tell.

Proxmox would still be useful for container management.

Does your budget include the drives you mentioned, or do you already own those? Do you have an esata dock or something already?

Oh I never looked at the two bay specs, good idea.

Synology specifically can run a bunch of services. Plex server is in the package manager. I use WebDAV and added it as a media source on the VLC app on my nvidia shields

The thing that you will struggle with, doing a roll your own NAS is that rolling your own is only going to be as reliable as you are.

I had a seadrive Linux server set up and I had a bunch of issues with accessibility and software upgrades because it stretched the bounds of what I was capable of. If I went back to that solution now, I would not struggle nearly as much and I would probably run two concurrent instances and transfer files between them instead of trying to upgrade the one live instance.

But I need something consistent for my wife and friends, so I did pick up a Synology 4 bay and loaded it with 4x 8tb drives.

With this thing, extra services beyond the Synology apps are much more simple to configure. Authentication is more consistent, even though I am not using the Synology sign in service.

The server hardware that was hosting Seadrive still has containers and VMs for a web proxy, pihole, my security camera server, qbittorrent-nox. I have a mikrotik router that feeds traffic back and forth.

If none of those things make sense to you even if you look them up, you should use a prebuilt. If you can make a guess how I’m using the things, you might be able to roll your own.