OVR Input and OVR Camera Rig

I have an Mac Studio with Unity 2021.3.2f1 installed - with Oculus integration. 

It is actually not possible to use the OVR Input prefab because the OVR Camera reference 

is greyed out. There is no possibility to drag the OVR Camera Rig prefab into it as mentioned in the document. 

Does anybody have a workaround for that?