We have RenderPassDepthGrab to grab the depth but CameraFrame currently does not use it. It’d be good to have it as an option, but it has not been done yet. Doing a prepass lets us do SSAO before lighting pass, and prepass was set up so that we can do velocity buffers for TAA as well. But an alternative, if those are not selected, would be good for sure.
You could extend CameraFrame engine class, and add RenderPassDepthGrab as a pass, or use the existing depth prepass.