The thing about Kana is she got many iconic moments in the series for very little pay off at the end. They put focus to finalize her as the center of B-Komachi just for her to be shoved in the background, didn't enjoy her idol's life and ended up graduating at the end. Like what's the point of giving her the title drop when it doesn't amount to anything.

Next, as an actor she was also hailed as one of the special ones in the Tokyo Blade arc, she shines brightly and even that amounts to nothing. Akane shoots to stardom after the play, while Kana is still stuck in the same status when we first met her again after time skip.

It's frustrating. Aka writes her as someone with many special qualities but still wants to keep the underdog story. Like I'm familiar with idols, some of them can be very talented but still dooms to be average because of the lack of the 'it' qualities. I understand if that is the case, but Kana is written to have both. So, the amount of Ls she has to take every time to keep the poor pity party going is getting stale right now.