This message was deleted.

No guarantee! Modifying the cluster resource directly should work: Add

spec.displayName: new-cluster-name

. Example:

apiVersion: <http://management.cattle.io/v3|management.cattle.io/v3>
kind: Cluster
metadata:
  annotations:
    ...
  labels:
    clusterGroup: cyrannus
    <http://provider.cattle.io|provider.cattle.io>: rke2
  name: local
  ...
spec:
  ...
  displayName: helios
  ...

Don't change

metadata.name

! Result in screenshot.

Okay that was easier than expected, will try myself on some less important clusters. Thank you very much!