当て馬大好きセシリアちゃん ~ヒロインの姉に転生したので、負けヒーローの推しを救います~

Synopsis

I've always fallen in love with the second male lead and I was reincarnated in the world of my favorite shoujo manga, "Suiore (Sweet Orange Ale)"! When I found out that I had been reincarnated at a period where the final volume was over, I was so excited to be able to see a future that I didn't know of yet, but many of characters including the two who ended up together, didn't seem happy as they all had their own complicated circumstances. I'll take you to the world of happy endings!!! (Source: Kadokawa, translated)

Anime adaptations