One surprising things the Gra wrote is "The root of the souls of gentiles is from heaven and the root of souls of Israel is from the land of israel." From what I recall this is from his commentary on Shir Hashirim chapter two [right at the start of the chapter]. So the idea of superiority because of birth seems to be in accurate. I saw a similar idea in Rav Luria on Genesis in a verse on the three sons on Noah.I.e., that their root was from the three names "I will be" אלף הי יוד הי. אלף הא יוד הי. אלף הה יוד הה