Regarding the horizon...
If you are 6 feet tall,
and you are standing on the beach looking out to sea at a ship,
if the top of the mast is a hundred feet above sea level,
you will still see the top of the mast at a great distance away.
The reason for the great distance is the great curvature of the earth. If the earth globe were not so large, the horizon would not be so far off. The distance is what makes observations unreliable... because of atmospheric aberrations, etc.
If you were the same 6-foot-tall person,
at the same place on the beach,
looking out at the same ship,
but you were buried in the sand up to your chin,
(like people bury themselves in sand at the beach),
the ship would have to be a lot closer,
so that you could see the same part of the top of the mast,
as you did when you were standing on the beach.
When the ship is closer, you get a much better view because of less aberration of the atmosphere, and less interference from whatever other atmospheric effects and conditions. Now that you don't have the atmospheric effects, you can clearly see that the earth is a globe, as the ship goes over the horizon.
When you are on straight and level land,
and you place your eyes near the ground,
by the side of a straight and level road,
(maybe get into the ditch),
the horizon is so near and the atmospheric aberrations so limited,
that you can easily see the horizon effect of globe earth,
in the way a moving car gradually disappears over the horizon.
You don't need some silly ship-at-sea thing. Everybody can do this right where they are at. You can use your digital camera. The distance is so close that even if you use a fish-eye lens, the effect of the lens will be negligible regarding how the car goes over the horizon. Any mirage-like atmospheric effect will be so small that it will make no difference with regard to the car clearly going over the horizon. Now, you can tell the earth is a globe, by eye or by camera, no matter who you are.
Of course, the above will have to be modified in some ways. My directions may not be exact for you and your location. You will have to consider your own details for your own location. But almost anyone can figure out how to do this enough to prove that the earth is a globe.