you can perceive depth from one vantage point,

Yes, with two eyes. Those are the two vantage points which allows for the brain to process the parallax into experiential depth.

With one eye, that can’t happen. It’s just like watching a tv. Without the 3d glasses, you will not experience depth. You can still infer depth (from artistic perspective, light and shadow, etc. but the image you are viewing is 2D and 2D has no depth. Please let me know if you still disagree that 2D has no depth.

question is beyond the diffraction limit, so depth never reaches your eyes.

There is no depth in a 2D image, and images of things beyond the diffraction limit can’t be seen as anything but a blur... You fundamentally don’t seem to understand what the diffraction limit is, or why.

Depth is not required to see an objects angular size.