"If you want to be the first in a genre, you have to create it," I think this is exactly the formula that the director of the film used, because Annette (as it should be for auteur cinema) transcends genre conventionality. I would describe it as a mix of "La La Land" with its plot and music and "Dogville" with its cinematic experiments with form, as well as incredibly cool music from the band Sparks (who are the ideological inspirations of the project), various operatic and, most importantly, theatrical performances. This is important because we are made to understand from the very beginning that this is a show for the audience, thereby exposing the reception and bringing it all to the level of meta-speech. And this theme of duality will be further developed in the film, for example, on the level of form: the relativity of the musical and the irrelevance of the drama.
In "Annette," the characters sing everywhere. Literally (so it's advisable to watch in the original). Which, of course, has a sort of embarrassing effect on what's going on. Moreover, these songs often have a rather simple content: "We love each other so much." But, come to think of it, don't people sing anywhere in life? At least in their own heads? In the film, the songs (sometimes even the dialogues are sung) are materialized, reflecting the inner struggles of the characters. As for the content, it could not be difficult a priori, for one usually sings what one can easily learn. And is it easy for a person to express his feelings in words, especially complex ones? Thus, conventionality is dictated by life itself.
It is noteworthy that after listening to the Sparks album of the same name, you can fully reproduce the plot of the movie, which I deliberately did not say anything about, so that you can enjoy it yourselves. Despite the fact that it is based on an ordinary love story, it is so incredibly and skillfully complicated due to, firstly, the chosen cinematic form and, secondly, the type of psychological analysis, introspection through songs, that even catharsis does not describe the feeling you have after watching it (by the way, there is an after-the-title scene in the film, don't miss it!).