It think it would've worked if while relying on her past memory, she still acts similar to her old self but just catches herself when she's about to say something terrible and reflects upon herself
It's alot more reasonable when they get their past life memories as a child and their personality changes because the have more memories as their past compared to their child self but it's never a slow change in personality, it's immediate which is off-putting

it’s nice but i just wanna express sumth cause im tried of when the FL “regained her memory for past life” she suddenly have a whole shift like “my past self has a trash personality” realistically her personality wouldn’t change but her mindset would yk? I like the strong fl type personality im getting tired of them turning into a common heroine.. but yeah