Find iOS device distance from user's face

I am trying to find iOS device's front-facing camera distance to user's face in the real world.

So far, I have tried ARKit/SceneKit, and using ARFaceAnchor was able to detect user's face distance from camera; but it only work in close proximity (up to about 88 cm). My application requires face distance detection up to 200 cms.

I am assuming this could be achived without the use of truedepth data (which is being used in ARFaceAnchor).

Can you put me int he right direction?

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