Despite the marketing of the first film hinting at a larger role for the actress in the film, Chani appeared mainly in Paul's dreams before finally meeting him at the tail end of the movie.

Source: https://collider.com/dune-part-2-chani-zendaya-comments/

In the article Villeneuve gives a lot of credit to his two leads for “figuring it out,” saying that Chani is “a fierce warrior… but there’s something about that young man that cracks her heart.

Source: https://gizmodo.com/dune-2-romance-zendaya-timothee-chalamet-pictures-1850382335

Timothy Chalamet's Paul Atreides will continue to be the central character, while figures such as Javier Bardem's Stilgar and Zandaya's Chani will play larger roles.

Source: https://screenrant.com/dune-part-2-story-cast-updates/