To prove that Earth is flat, you have to prove that gravity isn't real.
To prove that gravity isn't real, you have to prove that Earth is constantly accelerating at approximately 9.8 m/s^2.
To prove that Earth is constantly accelerating at approximately 9.8 m/s^2, you have to prove the speed of light isn't an absolute speed limit.
To prove that the speed of light isn't an absolute speed limit, you have to prove that electromagnetic waves don't exist.
To prove that electromagnetic waves don't exist, you have to prove that electricity doesn't exist.
To prove that electricity doesn't exist, you have to prove that you're looking at a black empty slab and you're projecting images from your head.
And even if you do prove the Earth is flat then why are you adding this part in?

If the Earth was indeed a disk shape then the centre would feel pretty normal but as you begin to move towards the edge gravity would skew and begin
to face inwards. This means that it would feel as though you are climbing a hill when it is completely flat therefore the issue would not be falling off
the edge but instead falling back to the middle, and if that were the case then why has no-one found this hill?

If the Earth is flat then how thick is it? Is it so flat that it's ivisible from a side angle? Or is it thick enough to be visible from a side angle, if
this is the case then why can't we get to this angle which leads to the side of the disk?

To argue with Eratosthene's method of measuring the circumference of the Earth using the different shadows cast by poles then you would have to explain
the heat produced by combusting hydrogen being different to that on earth than it is in space and re-explain radiation and gamma.

And just to cap things off explain how The Flat Earth Society has members all around the globe.