So the confusion in your mind (implied but not established) about how perspective works somehow discredits a horizon greater than ten miles away, when it can only be three on a globe?

A lighthouses height makes sense if you understand perspective on a plane. The globe theorist knowingly conflates perspective, convergence and a litany of atmospheric effects with the theorized effects from curvature because, the optical effects in mathematical terms are a close (but not perfect) match. After doing this the theorists who know they are in error, start a gas-lighting campaign and go "Duhhh, what's perspective?", "Of-coarse objects get smaller as they go father away!", "You could see London from New York if it were flat!", "Refraction causes the horizon to rise!", "Boats sail over the curve!", "NASA proves images from space on TV!".

On a plane,



the ground is perpendicular to the viewer,



however it rises optically to the vanishing point,



at eye level,



and objects traverse a vertical distance optically,



as they physically move away horizontally,
to converge at the optical vanishing point.



If you raise the viewers eye level, then it takes more physical horizontal ground to traverse the optical vertical distance to the higher level and thus, the viewer can see farther.

If you're too stupid to learn about perspective on a plane (or are just a liar) and insist on error, then you need to find a gas oven and get the fuck inside.