Hehe- monks from ME-DEM here.
Aman was removed from Middle Earth at the Cataclysm. ME-DEM are building the M-E post Cataclysm (3rd Age).
M-E was intended by Tolkien to be Earth with an alternate timeline/ history, hence why it can be mapped as an Earth sized globe.
One is to view the pre-Cataclysm M-E as flat much like pre-
Renaissance men thought Earth was flat.
My personal view is that Elves and Men exist with different projections in their heads: that is Elves see the world as still being flat (and whatever else), whereas Men see it as being spherical (in spherical projection). This would/could account for the ability of Elves to see extremely long distances because they don't 'see'/ experience the curvature of the Earth: I remember an objection to Legolas being able to see Minas Tirith or something....hence why Elves are able to take the 'Straight Road' to the Undying Lands. This fundamentally different experience of the world would also account for why Elves can 'fade away'.