It depends on your perspective. Some elements of the story may have roots in real events, but it's also likely that there's some fictionalization for dramatic effect. So, it's a mix of both.
In fact, 'Nobody Knows' has its roots in a true story. The filmmakers took elements from a real event to create this narrative, giving it an added layer of depth and authenticity.
I'd recommend 'The Silent World'. In this dystopia, communication has been severely restricted, and the characters must find ways to break free of the silence.
In 'nobody knows my name novel', a possible theme is self - discovery. The protagonist, with no one knowing their name, may embark on a journey to discover themselves without the influence of external recognition. Also, the theme of social alienation might be present as not being known by others can signify a lack of connection to society.