As Admin user:

• create user
• import clusterrole-stupid-reader.yaml
• import clusterrolebinding-gib-stupid.yaml
• import clusterrolebinding-gib-dashboard.yaml
• install obo quay.io/rh-ee-pyurkovi/observability-operator-bundle:1.2.1-short-time
• install Monitoring UIPlugin
• create perses-dev project/namespace
• install perses dashboard and perses datasource from here: https://github.com/perses/perses-operator/tree/main/config/samples/openshift

1. Log as user
2. Go To Observe > Dashboards (Perses)
3. Result: user has access to:
   1. observability-operator namespace with Accelerator dashboard
   2. perses-dev namespace with Kubernetes% dashboard
4. As Admin user in other browser, delete cluster role binding for dashboard
5. As user, refresh browser
   1. Result: You still have access to dashboards
6. Logout and login as user again
   1. Result: You still have access to dashboards

Note: It took longer (I cannot precise how long) to take effect.