If you want a cloud use Nextcloud. If you want a simple small NAS use OMV. If you want a complex big NAS and you got good enterprise grade hardware use TrueNAS.
And what storage to choose for each of them really depends...its always "pick your poison". All options got heavy drawbacks and you have to choose the lesser evil for your personal needs.
Bind-mounting won't work for 2 years or so as the "sharerootfs" plugin in OMV is required for that and not working anymore.
If you want OMV use a VM with
disk passthrough or virtual disks.
And be aware that you won't be able to mount SMB/NFS shares directly inside an unprivileged LXC...that only works with secure VMs and insecure privileged LXCs. So you will have to cut corners again and choose between secure but expensive or insecure but cheap on ressources.