Who can picture the Legion having a fictional country similar to Marvel's Wakanda-home of Black Panther????
The United Planets with it's dozens of worlds, is Wakanda x Infinity already!
Plus they live in Metropolis, a fictional city, on a 'united' Earth, which is pretty much a fictional country of it's own (that picks it's President by computer!).
Isn't that Marzal Island?
Its technology developed independently from the rest of Earth, but when Dawnstar and Shadow Lass visited, it appeared equally as advanced as 3Oth-century Metropolis, if not moreso.
While most of the UP cover the 'technological utopia' aspect of Wakanda, Marzal certainly takes on the racial monoculture aspect, as well.