Who said it had to be a constant height in the sky?
I almost has to be at a constant height in the sky over a flat disk, otherwise a person in Russia would see a Sun one size, lets say 5 cm, and someone in London would see the Sun a different size, lets say 3 cm if it is getting further away over London, and someone else in Canada would see the Sun with a third size, lets say 7 cm if it is getting closer. The Sun's size does not change significantly no matter which side of the world you are at the same latitude or during the course of the day, two highly conflicting ideas