Apple allows FaceTime to adjust the eyes of the viewer when calling video calls to each other, giving the feeling that the two conversations are always looking at each other on iOS 13 beta 3. That's thanks to the ARKit emulator on the Bionic A12 chip. This means that it is currently only available on iPhone Xs / Xs Max (not yet available on iPhone XR).
If you're using Xs or Xs Max, go in Settings – select FaceTime and turn off the FaceTime Attention Correction button.
Usually we call FaceTime together just looking at the screen but no one looks continuously at the front camera, so it always feels like 2 people don't look at each other's face naturally. Now thanks to this small change on iOS 13 beta 3 will help overcome that, although it is only a beta but the emulator's eyes look quite natural, not too fake, even if we look at the screen it still makes sense of looking straight ahead (not creepy like many people think).
Hopefully in the future, Apple will promote this feature for lower iPhone models.