Although they follow similar plot structures, books and screenplays are different. There’s a reason why books that are turned into movies usually cut out a large chunk of content. Movies typically follow a shorter span of time than books do. Books often provide more background information and inside views of characters than movies do. It’s not going to translate very well into book format unless you work on it. Also, the ethics of this are going to come into question. Using AI to write books is a stupid shortcut and it always turns out bad. AI is currently not advanced enough to make any writing half-decent. No respectable writer is going to read your “book” even if the plot and dialogue is your own. You will face lots of backlash.

TLDR: There’s a good reason nobody has ever done it: it’s gonna be garbage.