I don't understand why you unironically think this is a rebuttal. We can see the earth, you literally said it yourself: "we can't see it from all sides at once," implying we can see it from some sides. We derive our understanding of it based on what we see. We cannot see it all at once but there are still observables to see from which we can derive the deeper mathematical structure from those observables.

A better analogy would be: consider how we learned of the existence of magnetic fields. You can scatter some iron filings around a magnet and they will conform to the shape of the field. We do not see the field directly, but its effects, and we derive the properties of the field by the effects it has on visible particles.

Now, imagine if someone comes along and says the iron filings don't actually exist, only the field. You'd be a bit confused, because you derived the field and came to understand it from the iron filings. You can't even see the field directly, so what does it even mean to say only the invisible field exists?

That is literally what you are doing. MWI has no observables at all. We live in a world filled with visible particles in spacetime from which we derive the Schrodinger equation from observing the behavior of those particles. It is a mathematical relation used to predict the motion of visible particles. MWI proponents them come along and say, "actually the particles in spacetime don't exist, only the abstract mathematical waves made of nothing floating around in Hilbert space that we use to predict where particles will show up exist!"

How do you think that is any way comparable to seeing different sides of the earth and then concluding it is a globe? The different sides of the earth are observables, there is still something we can see to derive the underlying mathematical structure. There are no observables at all in MWI.

"[The Many Worlds Interpretation] does not account, per se, for the phenomenological reality that we actually observe. In order to describe the phenomena that we observe, other mathematical elements are needed besides ψ: the individual variables, like X and P, that we use to describe the world. The Many Worlds interpretation does not explain them clearly. It is not enough to know the ψ wave and Schrödinger’s equation in order to define and use quantum theory: we need to specify an algebra of observables, otherwise we cannot calculate anything and there is no relation with the phenomena of our experience. The role of this algebra of observables, which is extremely clear in other interpretations, is not at all clear in the Many Worlds interpretation." (Carlo Rovelli, "Helgoland: Making Sense of the Quantum Revolution")

I would recommend readers to watch Tim Maudlin's lecture on this subject, he covers the problem well.

This isn’t even to mention the fact that the Schrodinger equation is just one of several mathematically equivalent ways of formulating quantum mechanics, and so putting so much weight on it is just a bizarre notion from the get-go.