Up is up and down is down and the globe theory requires different imaginings of those concepts.
If up and down are experiential concepts then nothing need be reimagined, you just experience them. That’s the point of it being experiential, no abstraction is required.
You could say the same about us living in the Matrix. But imagining that things are some sort of illusion is not emperical.
Who is imagining an illusion? I understand that you disagree with how the RE works but surely you can see that your argument is specious at best? If gravity is real, and the Earth is an oblate spheroid, down in towards the center of gravity and up is away from it. Easily conceived and easily experienced.
If your argument ends up being “its wrong because it’s wrong” then you are not making an argument at all.