I run a Plex container on Proxmox and have it connect to my Armbian/OMV NAS via SMB. The way I got SMB shares working was to mount them from the Proxmox host and then mount them read-only from the container. (better security ig) I’d be happy to share my configs although it might take me a couple days to pull them up.

Another alternative I’ve been thinking about is buying an external drive rack and attaching it to the outside of my server’s PC case. Then running SATA extenders but this might not be possible depending on the kind of mini PC and I’ve heard extending power can get dicey if you have more than a few drives.