Schedule POD alone on a node
That is the problem that taints and tolerations was designed to solve
I would guess most kube-system things have a "universal" toleration, designed to work with all taints (and if not, one can trivially add one as follows:)
tolerations:
- effect: NoSchedule
operator: Exists
Then, you would just taint the Node with some nonsense key, and add the matching toleration to the Pod or Deployment you wish to insolate