From observing some users within Proxmox, and looking within Github there are ways to use the NoVNC API to complete additional functions for VM's such as restarting, shutting down and other functions.
Was wondering if this was on the roadmap, but as this is a lower priority, happy to have this be something that someone can look into as that would be a nice to have within Unraid's NoVNC implimentation that would bring it up to spec with Proxmox.