Unable to edit or delete Immutable Protection Group after creation.
VMware vSAN Data Protection(all versions)
Per Using vSAN Data Protection documentation
you can enable immutability mode on a protection group for additional security. You cannot edit or delete this protection group, change the VM membership, edit or delete snapshots. An immutable snapshot is a read-only copy of data that cannot be modified or deleted, even by an attacker with administrative privileges.
Once immutability mode is enabled on a protection group, it cannot be disabled by an administrator.
If you are having issues with or need to modify a Protection Group with immutability mode enabled, please open a case with VMware Support for assistance.