Hi everyone. I deployed an RKE2 cluster with Rancher. After using the Rancher cleanup tool and re-importing the cluster, I'm missing a lot of features in Rancher, like the ability to choose upgrade the Kubernetes version. How do I get those features back?

You don't. You can't import a Provisioned cluster into another Rancher instance and get the same features. At that point it's just an imported cluster like any other. You need to back up and restore the Rancher data to the new management cluster if you want to retain full management ability.

Can i still upgrade rke2 by follow this guide? https://docs.rke2.io/upgrades/automated_upgrade