Demon's souls is a PS5 exclusive by Bluepoint. So I expect it to look and run better than Elden Ring which is a (semi?) open world crossgen game by fucking FROM of all developers. But Demon's Souls is an old game at heart, BP didn't change the fundamentals. Dark Souls 3 has much better and versatile gameplay than DeS. So I wouldn't rule out Elden Ring to have better and more advanced gameplay as well.