Multi clusters UI tool for increasing our customers UX?

Hi All, in my team we are searching a cool tool like kube-dashboard but for multiple clusters.
We have multiple cluster on top of several CSP in our caas offer. We run shared production clusters for our internal projetcs (growing everyday)
As we deploy and lifecycle these production cluster in CI/CD we don’t want to use tools like dockerEE or rancher who locks your kubernetes existing clusters. We dont appreciate that.
We host enterprise production workload and want to improve our customer experience.

So we prefer tooling with no effect on our way to run clusters, tools who just consume api-server and/or prometheus

Today if they want to have a consistent view of all their workload spanned accross all our cluster they must use prometheus federation ( to federate the prometheus we gave to them ) and with grafana do some graphs… can do part of the job but not so easy for our customers and so turnkey…
On the other hand, we tried ManageIQ. I admit we didn’t succeed in plugging the prometheus/alert-manager part, but for api-server works well, we see all kubernetes resources on all clusters. The real pain is that you can’t have several organization or vref, there is only one DB. and the RBAC is horrible. So not for production use for us.

If you have any idea, feel free to share, we search a read-only tool, we dont want user trigger someting from it, only for reporting yet.

Best regards