Manga about a female lead who becomes the aloof male lead's sister

Question

In the beginning, the female lead is isekaied to a novel or manga she read and becomes a character that was never in the book. The female lead has a brother who is practicing sword fighting with a knight and his eyes start glowing as he is getting really into it. The female lead is his younger sister and holds his face, telling him to take it easy on the sword fighting; his eyes stop glowing and he smiles. It cut scenes to him and her at two graves which belong to their parents and he is now in charge of the nobility and lives with her. I think the male lead had white hair, but the young female lead also had a bond with a woman who wore a mask outside the house due to an accident and her face was burned. At one point the female lead saved her from herself blowing up at a party. At that same party she was introduced to the original female lead of the story, and found out that she was hired to become her bodyguard by her older brother, who I'm pretty sure was black haired.

I'm trying to remember what it was, but I can't for the life of me.

Answer 1

OMG Y'ALL I FOUND IT!!! It's a manga called The Strongest Characters in the World are Obsessed With Me yaaaaay!!! :).

From Anime-Planet:

One day when she was thirteen years old, while chewing bread as a snack, Dalia Pesteros suddenly remembered her past life. This is an impoverished otome game world where the main characters go crazy, and she was born as the sister of the worst villain in the future! There is no solution at this rate. The family will be exterminated, and I will be thrown away. So, no matter what, I must get out of this family as soon as possible! ‘Now that it’s like this, I need to lower their guard and run away.’ In order to get rid of the relatives who aim for the family and the sly emperor, it’s better to be in good favor with my brother- “I want to dance with Dalia. What’s the problem?” “I’m sorry, but my sister is shy.” “Dalia said I was her favorite!” Somehow, it’s not only my brother that I tamed, but all the strongest characters in this world are obsessed with me!