There's really nowhere else to go after the S8/S9 all but removed the bezels. The phone itself is a screen, which has been the holy grail of smartphone design for almost a decade. Now that it's been achieved, anything else will likely just be a gimmick. "Look, we got a cool notch!" "Wowzers, this phone is foldable! That's a cool feature nobody ever asked for!" "Our notch is now 22% smaller than the previous notch!"