Recover access to orphaned cluster

So I lost my Rancher server badly and it’s unrecoverable. I had a cluster set up with that server. The cluster is still running, I can access the workload frontends. I was able to recover access through kubectl with the help of a saved kubeconfig so I thought I’d set up a new Rancher server and import the cluster into that. Just to find out I cannot move cluster namespaces into Rancher projects so that they become visible on the UI. Also it seems that the import changed the credentials (a new user account was created at least), so the kubectl access doesn’t work any more.

I have ssh access to the nodes and able to see the containers through docker cli. Is there a way I can get the credentials back to configure kubeconfig again?