Perhaps 'Fanfic about finding pleasure in letting go and surrendering'. This takes out the disturbing brainwash idea and instead focuses on the idea of surrendering in a more positive light, like finding peace or pleasure in letting go of certain things or control.
One way could be 'The journey of self - discovery through surrendering in a fanfic'. Here, we remove the negative brainwash aspect and focus on a more positive aspect of surrendering which can be related to self - discovery or growth.