Hum…sorry, I’m not aware of any material that is specific to Nomad like this. But in general, a non-Nomad comparison would be a fairly good start.
CoreOS and FlatCar are operating systems, not runtime engines. I haven’t tried it myself, but I’m fairly confident that Nomad would run just fine in FlatCar since it’s a Linux-based OS. FlatCar supports multiple container runtimes, including Docker and containerd.
Nomad has built-in support for Docker, while containerd is provided as an external plugin.
How do one compare to the other I can’t really say since I don’t have much experience with containerd myself.
I never tried to mount Docker volumes in Nomad, but I think it would be possible using the mount attribute? But I could be wrong.
That’s a great ask! Unfortunately I don’t know any on the my head, so I would like to see something like this as well.
Maybe there’s something in our resource library?
I know there was a talk about CSI and stateful workloads at HashiTalks this year, but I am not sure if it covers what you are looking for: https://www.hashicorp.com/resources/dont-afraid-csi-how-critical-techworks-orchestrates-stateful-apps-hashicorp-nomad
I’m sorry I don’t have a better answer for you 
But hopefully someone else from the community will be able to share some of their experiences.