This is what I wanted to get at, in that she has "lived" another timeline of sorts, so her story would or should take a step back. At the start of the comic, she worked like this to the best of her ability, in having a goal oriented mindset where the story of others matters less (forcing the marriage and jumping him in bed), and she became less connected to those around her.
I don't really get that vibe from her, if anything she got more desperate exactly because she cares about the people she love and don't want to lose them.
Her personality is just... unique, to say the least. She's not entirely "less connected" because she is goal oriented, she just seems like that because she doesn't act like what people expected her to be, a typical noblewoman who should've been scared by her husband, vs her actual caring self who doesn't really conform to proper lady behavior.
She didn't force any marriage, she selflessly "sacrificed" herself to save the world while at the same time so her cousin doesn't have to marry him (the marriage is happening regardless of who would become the future-duchess). She is crass and lack grace, so she just jump on him every chance she gets in the beginning but only because she wasn't aware of her husband's grievances; after learning about it she holds herself back knowing that it'll hurt the Duke, because she actually cares about him.
Just in case you forgot, she went out of her way to solve a case where maids (the lowest on the totem pole of a noble house) became victims, it had nothing to do with her goal and she have no real obligation to pay it any attention.
As far as I know in the "original timeline" she just never met the duke in the first place, there's really no tension about being isolated from others nor connecting with more people. Your Starfield comparison implies that she might be jaded by repeating her lifetime, but from her perspective this is her one and only chance, she only ever "came back" from the future once (not even remembering any events prior to her waking up in a nightmarish future). Remember that the supposed "original timeline" is just a prophetic dream to her, she didn't physically time travel back into the past or into another timeline. She desperately tries to sleep with the duke precisely because she think if she fails, the world will be doomed, and there's no retry.
For the lack of a better word, I think you are completely off the mark here sadly.