
Okay, I really like this!!
A lot of the time with these reincarnation type stories the 'other girl' who seems nice and innocent is actually very cunning and out to get your man, yet the younger sister in this is actually truly very sweet. And normally the 'other guy' normally the previous fiance (or in this case the prince) is stupid and mean too, yet (although I don't ship him with Yula) the prince is actually a decent guy here.
I like that all characters are good and just going about their own thing, too many times stories reduce the "other characters" into -20 IQ idiots for absolutely no reason and although I'm a fan of a few stories that doe this, I've got to admit that it's refreshing to see characters use their heads!

Okay so I know this is going to be hated, because how dare there be such a thing as constructive criticism, however I really don't feel that the MC is a character. The MC has no personality, she's literally just a puppet for the author to move around and tell the story of the people around her.
Even when horrible things are happening to the MC she just listlessly moves on. There's no personality. I know she's depressed, but she doesn't even have a depressed personality, she's just there moving about for the sake of other characters.

To me she does have a depressed personality, her depression being a symptom of her PTSD, or probably, more specifically, C-PTSD (the kind where it's years of abuse and a bit different from normal PTSD).
In the past couple of chapters, she's been trying to get better, and we're getting more of her personality cause she's finally dissociating less and doesn't constantly have to be on guard. And I think we'll start seeing her come out of her shell finally.
I'm not surprised you think she lacks personality tho, because prolonged abuse will change a person into something a lot of people really aren't familiar with outside of the war veteran version.

Again, I still don't believe she has a personality. She's still just a puppet to me and this is mainly because she moves and acts and speaks when needed for the plot and for the characters around her, but we never (or very rarely) get to see her thoughts.
The main dialogue with books and mangas is the MC's thoughts, they're the narrators of the plot. With this story the MC moves and speaks when needed but she rarely thinks or narrates the story.
The main amount of narration and thoughts come from either the emperor or the silver haired prince. Even the maids get more 'thinking dialogue' than the MC.
My point has really nothing to do with her personality or being depressed, it's mainly a flaw with the narration, the POV, a d the author.
I'm actually really loving this.
I've read a lot of reincarnation/transmigration stories and after a while they all start blurring together and it's hard to distinguish the good from the bad, but this is such a refreshing read.
I do think know how to describe it, but to me it kinda feels like I'm reading a bit of an old school manga? There was a point in time where all these harem stories were huge and I haven't seen that for a while so I'm quite excited with this (although we all know who she's going to end up with lol).