You know if I was the one writing this series, I would have Sakura run away go to fuckboi but Shinobu actually manages to find her, fuckboi tries interfering but Shinobu and Sakura actually gasp talk it out and come to understand the situation.
Sakura apologizes for running away, Shinobu likewise apologizes for making Sakura feel upset, fuckboi watches, silently brooding unable to get a word in.
Next day, blondie bitch tries convincing Sakura to join her agency while still mentioning that Shinobu is a good for nothing cheater but Sakura strongly rejects her and slaps her by telling her not to badmouth Shinobu, leaving blondie with shocked hollow eyes, after this blondie goes to speak to fuckboi and tries to play the whole situation off by saying Sakura wasn't even that good only for fuckboi to get frustrated and force himself on blondie in order to cope with not getting Sakura.
But in true Grapara fashion, blondie gives in and gets pregnant, thus forcing herself to retire and for fuckboi to take care of the baby, meanwhile Shinobu platonically supports Fumi and stays in a relationship with Sakura, until Sakura decides it's okay for Fumi to date Shinobu as well.
But alas I am not writing this series and honestly I wouldn't even dedicate a fic to the above concept anyway.