Hopefully, the characters that are now completely useless and boring, like Kaguya and Shirogane, get removed and the focus moves to new ships, which is the only possible solution for a romance genre.
Soft reboot / fake continuation with different characters is the only way without forcing drama and destroying current relationships. A method successfully used in thousands of romance stories and never ending soap operas.
The absolutely best thing that could happen would be Hayasaka seducing Shirogane, but too many people would be be very saddened by that and it’s an innocent sweet manga, so obviously won’t happen. Although Chika can be sometimes quite an asshole with huge ego.