Which CPU can take care of both HA and Frigate with the cameras (I will be using Google coral)?
Any 12th gen intel with built in graphics is going to be plenty capable of running HA + Frigate in this way
Can HAOS be installed onto new Z690 boards or should I use a VM on Windows?
It can be, do keep in mind if you would want to store frigate recordings on a network share or different storage drive to the one that the OS is on, you won’t be able to do that with HA OS. Windows VM would probably be the worst possible option to go with.
If the above mentioned limitation is not an issue for you then HA OS is probably fine, otherwise installing in linux and then running Frigate in docker along with HA in docker or VM would be preferred.
You may have misunderstood what I was suggesting, as I am saying the same thing that running HA OS directly wouldn’t be a good utilization. “installing in linux and then running Frigate in docker along with HA in docker or VM would be preferred.”
If going to use VMs then sure proxmox works, I personally just run everything in docker on my Unraid NAS and am very happy with that.