Bamwoo

I am looking for a manhwa/web novel where the female lead is an adult who transmigrated/reincarnated into the body of a noble family's daughter.
Here are all the key details and specific plot points I remember:
Family Dynamics: She belongs to a family with her biological father and two adopted older brothers.
The Brothers:
One of the adopted brothers is a magic user.
The other brother is a soldier/general who went to war, returned victorious, and has a visible scar on his face.
The Magic Water Fountain & The Dragon: She awakens or first communicates with an ancient dragon/dragon spirit through a water fountain.
The Tower Master (Villain): There is a corrupt Tower Master (a high-ranking mage) who conducts dark experiments on people—including on one of her adopted brothers. She can feel that he is completely rotten/corrupted.
The Father's Betrayal & The Experiment: The biological father eventually finds out that the soul in his daughter's body isn't her original soul. Believing the Tower Master can send this "foreign" soul back to her original world and restore his real daughter, he hands her over to him.
The God Ritual & Decapitation: The Tower Master was actually lying to the father; he intended to sacrifice her extra-dimensional soul to create/summon a God that would obey only him. The protagonist manages to break free and cuts off the Tower Master's head.
Near the End / Climax: Towards the end, she is resting with the dragon in a spiritual space/dimension. Her father and both adopted brothers manage to reach that space to find her. Even though they now know her soul is different and she isn't technically their blood daughter/sister (and even though she doesn't recognize them in that state), they accept her as their true family and come to bring her back.

Looking for a manhwa — villainess / transmigration / false heroine
I'm trying to find a manhwa I read a while ago, but I can't remember the title. It's a full-color Korean manhwa.
Here are the details I remember:
The female protagonist has black hair, and the male lead also has black hair.
The FL transmigrates into a novel/game-like world and becomes the “villainess.”
There is another woman who is considered the original/main heroine. She is extremely obsessed with being the person everyone loves and believes that she is destined to be loved by everyone.
However, there is a true villainess behind the scenes. She was the one searching for souls/people from other dimensions to send into this world so that someone could make the “heroine” pay for ruining her life.
Many people/souls had been brought into the story before our FL, so our protagonist wasn't the first one. They were basically caught in a repeating cycle.
Our FL eventually manages to break this cycle.
There is also a lot of drama involving the ML's family:
The ML has a brother who desperately wants to become the heir.
The brother becomes involved with the “heroine” and conspires with her against the ML.
The heroine is involved with the brother romantically, but she also wants the ML because she genuinely believes that everyone is supposed to fall in love with her.
The ML's father discovers what the brother did and sends him to war, hoping that he will mature and learn what it means to be a proper heir.
Later, the brother disappears into another dimension/world while following the heroine.
There is a scene where the FL and her family are put on trial. Her family is actually guilty and is sentenced, but the FL herself is saved at the last moment by the ML's family. Her family is not rescued — only she is.
The FL also becomes very close friends with a princess who has short gray hair.
Near the end, the ML's parents realize how badly they treated the FL and apologize to her.
There is also an important scene where the ML's mother interrogates the “heroine.” During the interrogation, she realizes that the girl has actually been extremely disturbed/manipulative since she was a child and had simply been pretending to be innocent. The mother had genuinely believed she loved/protected the girl, so she feels guilty when she finally understands what she was really like.
I also vaguely remember that, toward the end, the “heroine” is forced to experience/see the suffering she caused in some kind of virtual dimension/simulation, or something similar.
I know this is a lot of oddly specific details but I really hope someone recognizes it. I think the title had something to do with “Villainess,” but I'm not sure.