I don't usually go for movies that are blatant historical fiction, and when I do, I am often disappointed, but I was not disappointed with Mozart's Sister because of the quality of the acting, the quality of the props, the quality of the lighting and direction, and the quality of the music, which was written by Marie-Jeanne Séréro. The music he wrote as Wolfgang's sister Nannerl's music is distinctly un-Mozartian (in the Wolfgangian sense of Mozartian), and I found that it helped me to accept the plausibility of the person and events being presented, while allowing me to fully know that the film was a fiction.
The mainly-Maynard Solomon-informed Wikipedia article tells us pretty much what we know about Wolfgang Amadeus Mozart's older sister.
The film's representation of Leopold Mozart as a young father is quite plausible, and, while the character of Anna Maria, the mother of Nannerl and Wolfgang, is charming and loving, she doesn't look at all like a woman who had gone through seven pregnancies and/or one who had lost five children in infancy. The film does have its faults (it begins in winter, and within a few days it looks like midsummer), but it also presents the realities that a non-noble young woman of talent and ability would have faced during the 18th century in Austria and in Paris, if she wanted to develop those talents and abilities and become a composer.
This film poses a good answer to the question of why we have so little 18th century music written by women, or at least music written by 18th-century women who did not use pseudonyms and/or dress as men.