To improve the Plex transcoding options and off load the computation from the NAS, the plan is purchase a BeeLink EQ13 Alder Lake N200 16GB Ram and 500GB Drive, currently for sale at £215.
The Beelink will then have proxmox installed as the main operating system. A docker container for Plex and the other dockers that are currently hosted on the NAS box.
Theguide for plex install I will be following here.
A virtual machine for Hssistant OS can also be installed to run HomeAssistant.