All those photos are of flares. But if you use a filter you can take a picture of the actual light source. Which is what has been done above with the photos I showed you.
Can you find a picture of a light source which maintains its apparent size when moving into the distance that isn't due to flare?
That's what you'd need to put forward to support this.
The effects in Georgii Shipin's gallery (https://www.shutterstock.com/g/georgiishipin?searchterm=light) are due to an effect of camera focusing and aperture, not flares. We did talk about it at one point. Diffusion scattering or some such. I will see if I can find those old discussions.
I do find it remarkable for light sources to maintain their size, no matter how far away they are.
You are correct in that light sources never quite maintain their angular size as they move away.
For distant objects
angular size is simply
size/distance. It is usually expressed in degrees and then is close enough to
size/(57 x distance).
For example using Globe figures, the moon's distance averages about 384,400 km and the earth's equatorial radius is 6378 km.
When the moon is rising or setting (over the Globe) the distance from the viewer is simply the 384,400 km but if directly overhead it is closer by the earth's equatorial radius of 6378 km.
Hence the moon should appear about 1.7% larger when directly.
This is not noticeable, especially as there is rarely any nearby visual reference. The difference is even less if the moon is not directly overhead.
And the sun, at about 149 million km, is so far away that even astronomers cannot measure the distance using simple parallax with any baseline on earth.
Here the change in size change is only about 0.004% and totally imperceptible.
The sun and moon on any current flat earth model are, of course, a completely different story. In that case the distance may change by a factor of three or more, hence the problem.
It does suggest that the mechanism in Earth Not a Globe may be possible if this same sort of mechanism could occur in the atmosphere, which at times in contemporary literature is described as acting like a lens in some ways.
Lens flare (probably really just very gross overexposure) can certainly make the sun seem larger than it is when well above the horizon, making it appear to shrink as it loses brightness as it approaches the horizon.
Observations of the moon have no such problem, though it still quite possible to overexpose a photo the moon. The full moon is a very bright object.