"Hardcover sales have been so strong that Ecco has put off issuing a paperback edition, which is now tentatively scheduled for the winter of 2025. Booksellers expect that “Remarkably Bright Creatures” will have another sales spike when the paperback is released and if a screen adaptation is made (a movie is currently in development with Anonymous Content and Clubhouse Pictures)."
https://www.nytimes.com/2023/12/30/books/remarkably-bright-creatures-shelby-van-pelt.html
Clarification: The title originally said released “to theaters,” but the nature of the release (theatrical or non) was not the intended essence of the question.
Actually this might be close!
From May 6, 2025: "Director Olivia Newman wraps production on her adaptation of Shelby Van Pelt’s best-selling novel."
https://www.netflix.com/tudum/articles/remarkably-bright-creatures-cast-release-date-photos-news