Maybe now?

customers/base/kustomization.yaml

@@ -5,3 +5,4 @@ resources:
   - nextcloud-service.yml
   - redis-deployment.yml
   - redis-service.yml
+  - s3-service.yml

customers/base/nextcloud-configmap.yml

@@ -2,7 +2,6 @@ apiVersion: v1
 kind: ConfigMap
 metadata:
   name: nextcloud-configmap
-  namespace: customer
 data: 
   config.php: |
     <?php

customers/base/nextcloud-deployment.yml

@@ -3,7 +3,6 @@ kind: Deployment
 apiVersion: apps/v1
 metadata:
   name: customer-node
-  namespace: customer
   labels:
     app: customer-node
 spec:

customers/base/nextcloud-ingress.yml

@@ -3,7 +3,6 @@ apiVersion: networking.k8s.io/v1
 kind: Ingress
 metadata:
   name: customer-ingress
-  namespace: customer
   annotations:
     kubernetes.io/ingress.class: traefik
     traefik.ingress.kubernetes.io/router.entrypoints: websecure

customers/base/nextcloud-pvc.yml

@@ -3,7 +3,6 @@ kind: PersistentVolumeClaim
 apiVersion: v1
 metadata:
   name: customer-shared-storage-claim
-  namespace: customer
   annotations:
     volume.beta.kubernetes.io/storage-class: openebs-jiva-3repl
 spec:

customers/base/nextcloud-service.yml

@@ -7,7 +7,6 @@ items:
     labels:
       app: customer-node
     name: customer-node
-    namespace: customer
   spec:
     ports:
     - port: 80

customers/base/s3-service.yml

@@ -3,7 +3,6 @@ apiVersion: v1
 kind: Service
 metadata:
   name: sto4
-  namespace: vr
 spec:
   type: ExternalName
   externalName: s3.sto4.safedc.net

customers/overlays/vr/test/kustomization.yaml

@@ -5,4 +5,3 @@ bases:
 patchesStrategicMerge:
   - nextcloud-deployment.yml
   - nextcloud-ingress.yml
-  - s3-service.yml