SOLVED. Historical Fiction: It follows the story of a young girl who is Hitler's niece and her coming to the realization that her uncle may not be as great as she thinks he is. [s]

[Rachel]

The book also falls in the genre of YA. Also, I'm pretty sure it's part of a duology.
I vaguely remember her meet a young Jew her age and visiting his home or neighbourhood or something and getting to see a completely different side of Germany, which starts the whole change in opinion towards her uncle, Hitler.

[Mai]

Maybe Prisoner of Night and Fog by Anne Blankman?
If it's not this one, when did you read it?

[Rachel]

Yes!! That's the one!! Thank you so much!! 😭😭