Don’t virtualize Active Directory on TrueNAS.
You could get away with setting up ProxMox as a hypervisor and then virualizing both the TrueNAS instance and the AD/Windows instance… Seems like you’d want two windows instances… one that has its zvol hosted on TrueNAS… and dependent on it, and another that is separate.
Which leads back to having a separate AD instance.
But that doesn’t mean you need the main windows instance to be separate.
Oh Dear.