Could you please explain how refraction, which requires specific conditions and sharp changes in atmospheric conditions, as well as distinct angles of entry/exit of the different medium, is responsible for all cases of an object being much more visible than the curvature formula dictates? I have yet to see one clear example of a distant object cut off at the expected amount due to curvature WITHOUT refraction. Nor have I seen an example of an object cut off more than expected due to refraction in the other direction (can't use up or down since globers often confuse this with refraction) ie. opposite from the upward/downward curve of globers bendy light.

There is no reason for refraction to only bring objects up and never make them appear more behind a curve. In any case I've looked at, the hidden amount could be more easily explained by refraction on a flat plane than refraction on a sphere. Atmospheric lensing that occurs as a result of diffraction, if I understand it correctly, seems more likely to be the case for objects appearing partially obscured (but still not nearly as much as required for the Earth to be a sphere). This could be proven with a test with very precise distance measurements and a known FOV calculation for the image frame. Or a picture suggesting curvature with the moon in frame as well, gives a fairly accurate reference point for determining apparent angular size. If a distant object is magnified just 30%, 15% will be hidden behind the horizon. If there is any magnification present on the globe model, it works against the expected drop and should make distant objects disappear even closer. We never observe this. I'm curious if you are aware of Anthony Riley's recent video showing the Isle of Man in it's entirety from about 100 KM away. Mountains in Ireland can arguably be seen as well at a globe impossible distance of well over 200 KM. The fact is there are many examples where extreme refraction doesn't even come close to accounting for the missing curvature. The refraction excuse is not good enough for me, sorry.