Regardless if earth is flat or not, we can agree physics are used to quantify and explain physical observations of the world we live in right? QED, EM, GR, SR, etc. Physics are derived based on observations of the earth as a globe. Why do these calculations match what we observe if they aren't true? eg. If 1 cube + 1 cube = 3 cubes observed while we calculate this as 1 + 1 = 2, then 1+1 =/= 2. However, we observe if you place 1 cube next to 1 more cube you have 2 cubes.
Suppose you still refuse to acknowledge physics, the mass of earth is 6 × 1024 kg, using Newton's law of gravitation/Kepler's 3rd Law. I haven’t found any flat earth mass calculations so I will use this one. (Based on the earth being a globe) If you take the calculated radius of earth, 6371 KM., this means the average density of earth is, 5.513 g/cm3. Meaning the volume is 1.0975095 x 1021 m3. Using the volume, and radius (found on flat earth society - https://wiki.tfes.org/Erathostenes_on_Diameter) you can derive the height of the 'flat earth cylinder.' Now we have an appropriate model of the cylinder at R=4.023 x 107 m, V=1.097 x 1021 m3, H=2.15 x 105 m with a mass of 6 x 1025 kg. Until flat earth society provides a mass estimate to derive the density we'll have to work with 6 x 1024 kg as the assumed mass. This means we now have a representation of a cylinder that can fit all of earth's, currently known mass, assuming the density is that same.
At this rate, our radius of the 'flat earth cylinder' is 25,000 miles or 40,233.6 km => 4.023 x 107 meters. Which was used in the calculation for our cylinder model. This means the diameter is 8.046 x 107 m or 49,995 miles.
Currently on a globe representation of earth, Los Angeles to New York is 2,797 miles with a diameter of 7,917 miles and radius 3,959 miles. Using this information you can calculate angle theta of a circular segment using the 2 radii (3,959 miles) and chord length (distance from New York to Los Angeles – 2,797 miles) of an SSS triangle, and then find the arc length of a segment of the circle. Which comes out to be 2,833 miles. 'Flat earth cylinder' has a diameter of 49,995 miles. Given these numbers, we can use (a/b) = (c/d) to solve for c. A = diameter (FE), B = Earth circumference, C = distance from New York to Los Angeles (FE), and D = Distance from New York to Los Angeles. Giving us the proportional distance between New York and Los Angeles . (49,995 mi)/(24901 mi) = (C)/(2833 mi). We can see using these same proportions after solving for C, Los Angeles to New York becomes a 5,687 mile trek. I suppose the mass could be conformed into a cone, or any different circular faced shape but per FES, the radius endorsed is still 25,000 miles, so this doesn't change our distance between the two, proportionally.
At 60 mph, this becomes a 94 hour journey to traverse the distance between New York and Los Angeles (5,687 miles), where as what is observed is a 46 hour travel time, to cover the distance 2,833 miles going 60 mph.
Flat earth non-sense is math/physics that doesn't reflect what we observe in our current physical world.