You can find the full script or subtitles for Avatar: The Way of Water in Portuguese (BR) by searching specialized online repositories and databases.
Avatar: The Way of Water subtítulo: Portugués (pt) - Open Subtitles Avatar: The Way of Water Legendas Portuguese (BR)
and Moviepedia are reliable platforms for locating the complete dialogue and translated captions for the film. You can find the full script or subtitles
Avatar: The Way of Water subtítulo: Portugués (pt) | 10 Subtítulo: Open Subtitles Avatar: The Way of Water Legendas Portuguese (BR)