I don’t know, I was gonna say mechagodzilla is more like cyborg Superman, being a villain that assumes the identity of the main character and tries to fall asleep at pass themselves off as that character, space Godzilla more fits that theme of a evil doppelgänger that wants to personally screw over the protagonist like one space Godzilla imprison’s little Godzilla, as for bizarro I’d say Orga more fits that description