Your entire argument here applies to sunsets on a FE. You call those an illusion.
Not without evidence. There is evidence that the sunset is a refraction illusion.
When a mountains and ships disappear from view the vanishing point is relatively close to the observer, maybe 15 miles away, and disappears uneventfully. When the sun disappears from view the vanishing point is thousands of miles away from the observer; and hence the sun is descending into thousands of miles of atmosphere which impedes its path.
If you've ever seen a sunset you would notice that a sun seems to merge into the horizon like a liquid as in the above image. That area where it's merging is the result of disappearing into the atmosphere. Fog lights shining through fog also have this liquid effect, where the light is broadcasted and projected onto the atmosphere, seemingly floating on the atmosphere itself rather than in the distance.
In FET this broadcast or projection of light upon the atmosphere is related to the
magnification of the sun at sunset.