How can AI writing be made competent?

I have a rather long manuscript for a saga, a story I finally got down to splash in text. The thing is, it's grown considerably, or rather, it's finally finished.

Soon I have to move on to the writing stage: prose, narration, POV, pacing, dialogue, style, pauses... I don't really have that much time to write, and unfortunately, I'm pretty terrible at it, and I think the AI ​​is much more capable of producing something.

And even when I do have time to write, I still want to see this story written and start doing beta versions.

I want to know how it works, or the best ways to make it capable of producing chapters with continuity, considering that I'll be acting as showrunner, there will be a complete script, and so on. So, what are the methods? Is there a way to create a style for it?