Originally I was very skeptical, seeing how mediocre Rings of Power was, and featuring a female protagonist in a story where she doesn't exist in the lore at all.
I rolled my eyes at the introduction, though its the same formula used in the trilogy, and I found most (not all) of the references to the trilogy to be rather lame or zero-value added.
However, I found myself pleasantly surprised and very entertained as the film progressed. While Hera is the main protagonist, there was not a point at which Helm or his sons felt overshadowed, which was the original primary concern. I found the film to be very exhilarating. Because of the fact that Hera doesn't exist in the lore, you don't know if she ends up surviving or not, and this adds a lot to the entertainment value because you don't ever feel that she's going to actually live.
Hera is a static character in the film, she doesn't change much, and this works just fine within the scope of the movie. In the end I find myself wishing there was more, or that there was actual lore surrounding her, which means that this movie was more than solid. Not a perfect movie, and certainly things I wished would have more depth, but this film is a fine addition to the universe.