So, let me get this straight. Your claim is that, on a flat Earth, we would not see a burning ball in the sky at different angles from different locations?
The angles would be different. And I think you know that's what I mean.
So, we would see the burning ball at different angles from different locations?
You are trying to turn this upside down.
We have a set of data, which shows at what angle the sun is visible at any point in time at any place.
That set of data can be verified.
If the data says 'the sun will appear X degrees above the horizon at location Y at time Z', we can go to place Y at time Z and check the angle X.
If the Earth is flat, the set of data would consist of different values for X, Y and Z than on a round Earth.
We can calculate this. If we use the current data and project this on a flat Earth, the numbers don't work anymore. They are inaccurate.
Since the numbers are accurate (we can check this) and the numbers ONLY work on a round Earth orbiting the Sun, the data supports the theory.
This means we can actually navigate by the Sun. We can find our location on the sphere based on the time and position of the Sun in the sky.