An iPhone XR doesn’t do the trick, does it?
Yes it does. All models post 2017 (Iphone X and beyond, with the exception of I think iphone SEs) include True Depth cameras (i.e. the device which allows depth estimation of the captured scene. It is mandatory for Apple FaceID or Unreal IOS facial mocap).
So iPhone X, Xs, Xmax, XR, 11/11 Pro, 12/12 pro, 13/13 pro should all support this. And in particular the XR (I have this model, Unreal live link face works well). I guess that recent iPads are also supporting this feature. Cheers.