If you have a single server, then the key value of z2jh is lost. If you dont have lots of other reasons for wanting to use k8s up-front, then go for tljh or a plain jupyterhub that you configure yourself from scratch i’d say.
Om tljh, you would use systemdspawner, so its docs about memory/cpu constraints would be of relevance. With regards to gpu constraints, im not sure.