Proxmox uses scsi for disk images, which are single access only
Smb would be quite a lot of overhead, and it doesn't natively support linux filesystem permissions. You'll also run into issues with any older programs that rely on file locks to operate. nfs would be a much more appropriate choice. That said, apparmor in container images will usually prevent you from mounting remote nfs shares without jumping through hoops (that are in your way for a reason). You'll be limited to doing that with virtual machines only, no openvz/containerd.
Fun fact, it was literally the problems of sharing media storage between multiple workflows that got me to stop using virtual machines in proxmox and start building custom docker containers instead.