BL Game no Shujinkou no Otouto de aru Koto ni Ki ga Tsukimashita

A woman who played a BL game is reincarnated into its world as the younger brother of the main character. She is surprised to discover that, upon realizing the situation, the older brother has already formed a relationship with one of the game's romantic interests. The other potential love interests are left to deal with the absence of the main character in their storylines. The main couple's future remains uncertain after the game's conclusion. The woman finds herself in a unique and advantageous position, though she is puzzled because the younger brother character was not part of the original game.