It’s easy to understand why this project didn't secure substantial financial support. It seems there's an idea that a female protagonist could take on the traditional role of a medieval hero, defeating monsters when the usual male counterparts were unable; and another concept involving two male warrior characters developing feelings for each other instead of women, which is unusual in that setting; and also, a black queen because it’s conceivable that within a largely white royal lineage, successive generations could have married people of color. While any one of these elements might be improbable on its own, combining all three right away—within the first ten minutes—gives the impression that the creators were trying to send a message. Considering how many similar attempts by studios like Disney/Pixar and others have failed at the box office, it’s not surprising major companies hesitated to invest. This was even before I got to know Nimona. My son, who picked this movie for our family night, questioned whether we should keep watching after just a few minutes. None of us wanted to continue because we weren't invested in spending another seventy-five minutes with such an irritating central character. We gave it fifteen minutes before stopping, which is unfortunate, since the basic plot—a regular person getting a chance to demonstrate their abilities and then being falsely accused of a crime to prevent them from joining an exclusive group—is a good one.

Source on TMDB