If a user has a pre-existing SMCP which is invalid, for example defining an attribute as null when it is expected to be a string, then it is not possible to fix without deleting the operator and CRDs.

Validation will fail with an error, for example as follows

Error from server: error when creating "smcp.yaml": conversion webhook for maistra.io/v1, Kind=ServiceMeshControlPlane failed: .redundancyPolicy accessor error: <nil> is of the type <nil>, expected string

and this prevents any manipulation of the resource (edit/delete etc).

The only fix appears to be uninstall the operator and delete the CRDs, tidying up the resource, and then a clean installation with the fixed SMCP.