Implementing FFR without OVRManager

Is there a way to implement FFR (Fixed Foveated Rendering) without using OVRManager?

Here's the info on FFR:
https://developer.oculus.com/documentation/unity/unity-fixed-foveated-rendering/

I don't want to install the Oculus Integration asset:
https://assetstore.unity.com/packages/tools/integration/oculus-integration-82022

I don't want the overhead or conflicts?

Thanks,

Vanz