The first thing to make really simple and clear is that during the Equinox everybody except those very close to the poles will see the Sun due East at dawn.
Anyone who is standing on the border between white and blue is looking right toward the Sun in this diagram, and that is the same as due East.
Therefore, if the Sun is seen due East at dawn in this particular day that is clear evidence that this model is correct.
Next point: since the easiest way to measure the azimuth of the Sun is through the use of a compass and the Magnetic North does not correspond to the Real North, you have to find the correction for your location. You can either search for a source for this information (there are many in the Internet) or you can find it yourself comparing the azimuth at dawn with the azimuth at dusk. In my case, the correction is 6 degrees West, so I have to subtract 6 degrees from my observed azimuth. 98 degrees (observed minus 6 degrees of correction is 92 degrees of azimuth.
Then, as in any scientific observation, some quantification of the error has to be made. In my case, the quality of the compass and the possibility of magnetic sources in the area were the most important factors to analyze. I decided, by repeating the same measurement several times in slightly different locations, that an error of less than 10 degrees is repeatably achievable. Plus, the measurement was made some 7 days late and a little after dawn. Those 7 days will make the azimuth decrease by about 1 degree every four days and the two hours after dawn would make the azimuth increase by about 2/3 of a degree per hour, so both errors approximately cancel out.
In conclusion, the expected measurement with respect to real science is an azimuth of 90 degrees and the measured result was 92 degrees plus or minus 10 degrees, or well within the expected error.
By contrast, a sun hovering above Earth in circles, about 3000 miles above Earth and, during the Equinox, hovering directly above the Equator, would be seen by an observer on the Equator at an azimuth of 45 degrees at dawn. Since I am slightly North of the Equator (4 degrees) we can draw a triangle that has the Sun over the Equator (6366 km away from the North Pole), an observer at 4 degrees North (6083 km from the North Pole) and the other point over the North Pole, with a right angle over the North Pole. Predictably, the azimuth that should have been observed, if the information above is right, would have increased to just under 47 degrees.
There is no way the observed azimuth was wrong by 45 degrees. Navigators have trusted their lives to compass measurements for centuries and survived, so completely wrong compass measurements would have to have an explanation.