I’m an amateur at this stuff and not at all familiar with the terminology, that said I had a similar setup to you I think, running a Windows PC with docker for P.O.-hole, homebridge, Plex etc. and then I was using an old MyCloud as the NAS. I got tired of troubleshooting issues and tweaking when things didn’t work and switched over.

Now I run an Asus Mini PC with Ubuntu and docker as a Plex server and P.O.-hole. The rest is handled by a Synology DS912+ running docker for a secondary Plex server, I have 7-10 individual users, a second pi-hole for failover and homebridge.

The Asus maps to the Synology on boot for the Plex media, all notifications for system issues/performance, out of date software etc. is handled by the Synology.

Ultimately it’s going to depend on which software you prefer I think. If you like OMV and it’s working well stick with it.