You are forgetting the most simple aspect of research. Going in the field and see with your own eyes with a 60x spotting scope if objects at different distances are disappearing/sinking behind the calculated horizon. How difficult is that?
Your research is not complete without this simple experiment.
Over the course of the last 40 years or more i have observed an object called the Sun dissapear below the horizon and also observed it becomes visible again when I go up a hill.
I have also over the last 20 years or so been aware that when it is cloudy at the coast and into the mountains that when the sun sets the distance mountains under the clouds are lit by the setting sun as are the under sides of the clouds even while there is total cloud cover from the mountains to the coast for tens of miles.
There is no need to observe these things with a spotting scope. You only need the spotting scope for observing a tiny distant object like a ship.
Only a very poorly educated or very naive person can believe the world is flat
You are forgetting the most simple aspect of research. Going in the field and see with your own eyes with a 60x spotting scope if objects at different distances are disappearing/sinking behind the calculated horizon. How difficult is that?
Your research is not complete without this simple experiment.
I can see you have no idea what research actually consists of. The simplest and first aspect of research is ALWAYS the library.
Science always builds upon the work performed by others in the field in order that time is not wasted just doing the same research over and over again. Otherwise we would just stand still and never make progress.
Do you honestly think that apple, dell, asus, intel etc go back to the start and redo all the research that has ever gone into resistance, inductance, capacitance, semi-conductors, PCB printing, thermodynamics, metallurgy, materials science....? No, they use what research has already been conducted, confirm its relevance and use it.
For the round earth argument. The prior research would be the greek experiments into the size of the earth, the enormous amount of information and evidence produced by the space industry and also my own eyes every time I look at the movement of the sun, the stars, perspective of the ground and sky, flight paths of aircraft, sunsets and sunrises, the horizon.
Sorry but dont need to go out and confirm with a spotting scope the evidence is already there and has been repeated countless times.