Is the VM using the USB drive at the same time?
No, I have an extra USB drive to test it out.
FWIW, I ended up just using a VM when probems like this would inevitably crop up with LXCs running software which goes too far off the garden path so to speak. My knowledge is a lil dated as I set most of my shit up about 2 years ago but at that time I got the distinct impression that LXCs were not fully-baked for running a number of things. Mostly I absorbed that info from reading the Proxmox forum. I'd love to hear if it's improved since 2021.
No idea. I'm new to proxmox and Linux by about 2 weeks, so I'm mainly just trying to learn. I figured since the tteck script sets up a LXC, it would be possible, but I can't really find any record of someone else doing it.
LXC and USB drives will give you problems. It'd be easier to run OMV as a VM and then pass the USB through in Proxmox web UI.
Proxmox
Proxmox VE is a complete, open-source server management platform for enterprise virtualization. It tightly integrates the KVM hypervisor and Linux Containers (LXC), software-defined storage and networking functionality, on a single platform. With the integrated web-based user interface you can manage VMs and containers, high availability for clusters, or the integrated disaster recovery tools with ease.