It would be to suspicious to suddenly fight everyone. Especially when she was a punching bag all her life. She is still unmarried so her status is not high yet. She need to be smooth and without controversy so crown prince won’t take interest in her more than usual
Yes unlike other regressor with bad reputation when they came back they can just push through their action, unlike this one who has different circumstances
it made sense for her to let lady florence (?) to punch her she needed solid grounds to kick her out, even if she's an imperial knight she doesn't have that kind of power so it was pretty smart to craft a situation that allowed her to kick her out.
Honestly, her attempt to change is quite questionable when she keeps allowing herself to become someone else's punching bag.