https://earthcurvature.com/


When you are out on your boat this summer or at the beach,, range the land you can see on a clam day, when the water is flat,,, use your phone to zoom in on the coastline,, then use one of these "Earth Curvature" calculators to find out how much curve their should be and how far below the horizon the coastline should be...

What you will find out is that there is no observable curve,, no matter how many times you do it you will not be able to observe the curve that does not exist...

At Sea level the Horizon is 3 miles away...

Everything out beyond 3 miles is below line of sight and not observable from ZERO elevation,, under our current perspective its impossible to observe what is below the Horizon from ZERO elevation...

What you will actually observe is that with magnification there is no limit to line of sight from ZERO Elevation,, you will find out that there is no observable curve...

Have done this several times myself from various locations and elevations...