Handle9:
I've got a Lenovo M92p with a 4th generation core i5, 16GB Ram and an SSD lying around. I'm considering migrating to Home Assistant OS and using this. As a bonus it'll give me the ability to monitor the Unraid server and run backups to the server etc.
Proxmox. 100%.
A HA VM will use about 1% of the M92p's resources, leaving plenty to play with for other stuff. And you can use all the handy backup/snapshotting features of Proxmox. It would be such a waste to install HA on bare metal on that box.