Super simple, like 30 minutes to setup mergerfs and then the bind mounts are a few lines added to the LXC config files at most. This isn’t necessarily needed, but I have users setup on the proxmox host with access to specific directories that are kind of a pain in the ass to remap the LXC users to, but were needed to give my *arr stack access to everything needed without giving access to the entire storage pool. Hard links won’t work across multiple bind mounts because the container will see them as separate file systems, so if your setup is /mnt/storage/TV, /mnt/storage/downloads, etc. then you’d have to pass just /mnt/storage as the bind mount.

On the other hand, I’ve been mounting my storage drives on the proxmox host with mergerfs and exposing what I need to the LXCs with bind mounts for years, and I haven’t had a single issue with it across multiple major version upgrades.

You can pass the storage you need to the LXCs with bind mounts. No network connection needed.