Hmm I get what u mean but I feel like its meant to be that the MC of the first part (when they were teens) was Aya, the story followed her and her emotions n stuff. The second part (when they're adults) Mitsuki is the MC and it focuses on her struggles with adulthood. Like the lack of talking atm is because Mitsuki is going through a rough time with her music career and she doesn't know how to express that to Aya. I think they'll work through it by talking in later chapters, after something happens yk I hope that made sense lol

i read this a long time ago back when only few chapters were out and i was dying for an update until it just became one of those unfinished mangas in my reading list (AKA VOID) but i came back after reading tweets that the mangaka focuses more on mitsuki and aya's basically just there and they fuck more than they talk like what