In upstream Kiali, many of the pages that requested resources (workloads, services, apps) once per namespace have been updated to instead request these resources once per cluster. Some of the namespace routes have been removed in favor of the cluster scoped routes. Backstage will need to be updated to work with the new responses and/or new routes for these pages.

For some examples see:

https://github.com/kiali/kiali/pull/7084

https://github.com/kiali/kiali/pull/7119

https://github.com/kiali/kiali/pull/7116

https://github.com/kiali/kiali/pull/7113