Ophie
Salingerian Phony
i honestly don't see it. Paldea is a landmass that's roughly the shape of the real-world Portugal and Spain, which is...a distorted rounded shape. So is Atlantis on that map. A distorted rounded shape is pretty much the most common shape for a fictional landmass.
I also see no reason for a Pokémon region to be based on a fictional landmass when they've been basing every region on a real-world real place since the series began. Game Freak starts doing research on a region's basis almost as soon as the previous generation began (so research into the Iberian Peninsula would've begun shortly after the release of Pokémon Sword and Shield, and research is likely already underway into Generation 10's region's basis).
I also see no reason for a Pokémon region to be based on a fictional landmass when they've been basing every region on a real-world real place since the series began. Game Freak starts doing research on a region's basis almost as soon as the previous generation began (so research into the Iberian Peninsula would've begun shortly after the release of Pokémon Sword and Shield, and research is likely already underway into Generation 10's region's basis).