Hey, I want to say its a bit off topic, but check out Jim's garage on YouTube regarding lxc nas folders, unprividged lxc setup. https://www.youtube.com/watch?v=DMPetY4mX-c

You may be trying to setup the folder in unprivileged lxc, which means you need to bind in your <containerid>.conf file under /etc/pve/lxc folder on the host(proxmox}

I hope this helps you.