I'm a Childhood Friend, and I Want to Remain a Supporting Character, but for Some Reason, I Became the Heroine's Love Interest

Osananajimi no Watashi wa Mobu de Itai noni, Nazeka Heroine no Ren'ai Taishou ni Natteiru.
幼馴染のわたしはモブでいたいのに、なぜかヒロインの恋愛対象になっている。

Alternative

manga

Yukitsuki Mashiro has been reincarnated into the world of a dating game. She decides to live an inconspicuous life as one of the heroines, "Amatsuki Suzuna," but after she helps "Hinase Riri" who is being harassed by a man in the downtown area, she becomes the target of love. What will become of Suzuna, who is surrounded by more and more heroines as everything she does goes wrong...?! Formerly known as "Osananajimi no Watashi wa Mob de Itai no ni, Nazeka Heroine no Renai Taishou ni Natte Iru." (Self-published version after serialization was cancelled)