Agreed, but I feel like Oshi no Ko is just a symptom of the problem
I didn't really interpret it that way. I actually read it as if Miki is afraid that her situation was gonna turn like Shiho and Aki's where the love was unrequited (at first) and then they had a falling out because of it. Don't know if Miki actually knows that Shiho and Aki are going out.
I really, really hope you’re right. I don’t want this manga to be ruined because of incest.
But you can see in this chapter page 29 a flashback where Aki told her about Shiho and she was clearly hurt at that so I'm sure she knows about her sister's relationship. I don't know but I'm pretty sure that she has a one sided love for her.
I don't like where this is going. I know that the incest plot is too common in Japan but I'll forever blame Oshi no ko for making this kind of route so popular! Miki don't you dare become a problem to my Akishiro ship please wake up and stop this nonsense ugh