The flat earth model is being promoted because it demonstrates reality.
I'll use my telescope example from another thread which was conveniently ignored by flat earthers because it couldn't be refuted.
The telescope is mounted on a clock driven equatorial fork mount to track the apparent motion of stars.
To work properly the polar axis passing through the arm of the mount must be aligned to the Earth's axis of rotation.
When the telescope is pointed straight up the declination reading illustrated must correspond to the latitude at where the telescope is located.
In this case the latitude is -37⁰ 45’.
For your flat model to represent reality you need to answer the following questions.
(1) Explain how the mount polar axis works in a flat earth model; what are you aligning the mount's polar axis to?
(2) Explain how pointing the telescope straight up gives the latitude at where the telescope is located on the Earth's surface.
If the Earth is flat this value will be the same anywhere on the surface.
(3) Explain why does the mount require to be clock driven which rotates the telescope around the polar axis of the mount when you claim Earth doesn't rotate.
A flat Earth with a rotating sky like the Ptolemaic model would make it impossible for a clock driven equatorial mount to track the stars.
It's over to you to explain how the mount can work in a flat Earth model; references to the Bible are not answers.