There is no reason you can’t get the stuff that is running on the DigiPi image to run on any other flavor/variant of linux, just install the image and apps and port the configs over. The stuff that Craig does really just makes configuring and using the tools much easier.
Note though, much of the usability of the image requires direct USB access, so your proxmox server would need to pass through the systems USB ports to the VM running.
Not sure what else to do as honestly this is not a configuration I would do. I prefer virtualizing systems for other use cases.