According to information provided by director Matt Reeves during an interview with The Hollywood Reporter, Bruce Wayne was written to be about 30 years old in "The Batman." Reeves specifically wanted this version of the character to not have the origin story, as he felt it was overdone, and he didn't want Batman to be a seasoned superhero this time around. Reeves set out to tell the story of someone who was still sort of figuring out what it meant to be Batman and determining the values he was trying to instill. As it turns out, this is a complete focus of "The Batman." At the beginning of the film, Bruce refers to himself around criminals as "vengeance," something that Selina, Oz, and The Riddler all refer to him as throughout the film, with The Riddler ultimately using it against him near the end. However, through that, Bruce finally realizes that he can affect Gotham as a symbol of hope rather than a symbol of vengeance.
Thirty-year-old Bruce also noticeably is going through constant struggles of balancing his life as a superhero with his public persona. Robert Pattinson noted in a recent interview that he and Reeves wanted to show a Bruce that hadn't quite figured out how to master the playboy facade of Bruce Wayne, and in the film, this is very apparent. Bruce truly only ever leaves the cave to actually be himself beyond Batman in service of his investigation as Batman.
