I think she is just a very humble person and quite selfless (which is kinda rare nowdays). Like you mentioned, her guilt of killing thousands is a bit weight on her shoulder and I think she only wanted to live in a small house with her brother. She also probably didn’t know a ton about how greedy and gross some of the nobles were because she was away at war for so long (like she didn’t even know that her brother was working and their “parents” was using her money for themselves). She technically did recieve some money, but having to take care of a title, land and a large mansion was probably a burden for her too.
Good things comes with problems and headaches. Especially to a Noble.
Look, she wants to amend her sins, she doesnt wants those things like title nor money because taking countless amount of life is much more valuable so she feels guilty.
"Why should I live happily when I killed so many innocent people..." that's what she's thinking. She has a big conscience for a girl like her.
I know many of you would take those rewards but do you really think you could live happily when the hands that you've used was once stained by blood of people who weren't even involve in the war?? That they were so innocent but you have to kill them because it was an order from your king. The knights from the other country who've fighting for not only their lives but also their country and their family, but you've killed them because you also can't risk your peoples lives. Its a burden to be a knight.
"No one in this world has the right to kill."
Yeah money is good, but someone's life is much more valuable. Please remember that.
I don't get her logic of not securing any rewards, titles or money for being a war hero.
She is way too modest and humble.
I get that she is a good natured person and feels guilty about the people she had killed during the war but refusing any given resources makes her an easy target by any rich influencial assholes.
We can see in the chapters that her male comrades/the MLs who loves her often save her day or solves her problems.
It is quite stupid that "I want to be just a commoner that lives a silent pieceful life" thought. Why not "I want to live a pieceful life but it wouldn't be bad to have some beneficial securities"?!