A film can have more than one protagonist. It’s actually very common to have co-leads.
EDIT: Maybe you haven’t been following this film at all, but the singular photo in this article was from a much earlier photo shoot that had the two leads standing side-by-side. It’s not an indication that Zelda is the sole main character of the film.
You said it’s unlikely but the article has Zelda as a protagonist, suggesting it’s quite likely.
A film can have more than one protagonist. It’s actually very common to have co-leads.
EDIT: Maybe you haven’t been following this film at all, but the singular photo in this article was from a much earlier photo shoot that had the two leads standing side-by-side. It’s not an indication that Zelda is the sole main character of the film.