Well, the story is about Shinobu and Sakura, so we all thought that even if things happened, they would ultimately stay together. It seems that chapter 128, when Fuckboy forces himself on Sakura and she gives in, upset Japanese readers so much that from that moment on, everything has been geared towards ending the story quickly. I suppose this is also due to disagreements between the author, the creative team, and the producer, and now the story has gone a bit crazy.
They could have shown Sakura's NTR but then resolved the misunderstanding with Shinobu and they stayed together, but instead, they showed an irrational Sakura who wasn't even able to confront Shinobu to resolve the situation. I don't know if that was the author's original idea or if, for reasons unknown to us, she got carried away and turned all the protagonists into hopeless idiots. I don't know if we'll ever find out.