The gist is to relax the check during upgrade-prep in the LCA to accommodate multiple versions of the applications across the fleet.  The backup CR  would include a superset of all the resources/api-resources to be backuped but on any particular manage cluster a subset exist.  This is of course contingent on oadp not having any issues with the missing resources on the managed cluster.

Also note, that the prep should fail if the cluster related resources for backup are not present.