At its core cockpit is like a modern day webmin that allows full system management. So yes it can help with creating raid devices and even lvms. It can help with mount points and encryption as well.
I do know it can help share whatever with smb and NFS. Just have a look at the plugins.
As for proxmox it’s just using Debian underneath. That Debian already happens to be optimized for virtualization and has native zfs support baked in.