I note the distance from the surface to the height at which the "flat earth" is visible seems to be restricted to less than 50 miles. In fact, in the videos, 22 miles is the height given. Which means that at that height, if there was a curvature, it would be around 160 feet of change.
So, when one is in the empire state building, can one tell the difference in height, in hundreds of feet? Note that the Empire State building is around 1200 feet high (not including to the tip). Can one discern, at that height, a difference of 20 or 30 feet in elevation on the ground level?
Let us utilize some math, for more accurate comparison:
22miles = 116160 ft.
If the earth curves at around 8 inches per mile. At 22 miles high, the distance one could see, theoretically, given the limits of the human eye, is 132 miles, or 696960 ft. That distance should yield a curvature of 88 feet in difference.
At 1200 ft, theoretically, one can see 42 miles. Which means, one should be able to see a curvature of 28 feet. At the height of the Empire State building, can one discern a height difference between two buildings, theoretically, at the end of visual range, and determine the height of those two buildings, with accuracy, with an error of less than 30 feet estimate?
I would say that a person could not discern visual difference, at 1200 feet, of 30 feet differences in elevation, as pertaining to ground level. We know that increased distance further lessens one's ability to discern differences. To increase that distance to 22 miles high, I seriously doubt in an individual's ability to discern distances of 100 feet, let alone less than that.