Extra volume mounts have root permissions, nextcloud can't access them.

Extra volumes declared in the values.yml file are successfully mounted in the nextcloud container, however, they are mounted with root:root permissions, therefore the Nextcloud instance can't access those folders, resulting in a popup notification saying "This operation is forbidden".

This simple configuration:

  # Extra mounts for the pods. Example shown is for connecting a legacy NFS volume
  # to NextCloud pods in Kubernetes. This can then be configured in External Storage
  extraVolumes:
    - name: nfs-shared-files
      nfs:
        server: "<REDACTED>"
        path: "/volume1/Shared Files/"
        readOnly: false
  extraVolumeMounts:
    - name: nfs-shared-files
      mountPath: "/mnt/shared_files"

Results in the following:

Is there any property that I'm missing?

Start with values.yml and trace how extraVolumes and extraVolumeMounts are rendered into the Nextcloud pod. Check the resulting Kubernetes volume permissions and the chart's existing pod or container security settings. Done means the mounted extra volume is accessible to the Nextcloud instance without breaking the supplied NFS configuration.