I'm professionally invested in AI and have been for over three decades. I've built my own neural nets and understand how transformers work. I'm yet to find any chatbot that can produce a decent story. I have a prompt I like to give chatbots just to test their 'creative' writing abilities*. So far it's never produced anything with any real spark. Its writing is anodyne and veers to passive. You will never find interesting word play or turns of phrase coming from a chatbot. Basically AI is not a good writer, and I'm not sure it ever will be, no matter how clever, because good writing comes from lived embodied experience.
However AI is very good at stuff like 'go through my manuscript and list every song lyric or musical reference', or 'check the dates in the manuscript for basic continuity errors', or 'check the spelling' (yes I know any spell checker can do this but an AI can tell you meant thought when you wrote through.) But that said AI is no replacement for beta-readers, a good editor, and friends.
So it's a tool. It has its place. Another very key point, quality of AI writing issues aside, is copyright. You can't copyright text you didn't write. If you used an AI to generate your text then you don't own it and you are not eligible for copyright protection for it. You can only claim copyright on your own original work. So if you use AI to do your writing for you, then you can't ever expect to get a real publisher, and if someone just steals your book (a common but unrealistic fear for new authors) you've got no rights and no recourse.
I am very careful never to let GPT anywhere near my original manuscript. If someone wants to accuse me of using AI to write my novel, well I can show every edit going back five or more years. I've been using Pages for years but now Apple have astroturfed it with their lame Siri AI tools I am considering switching to something else. I export from Pages to docx and from there I have written my own custom software to turn that into website, epub, and the various print PDFs for paperback and hardback. Codex has been great for the software side of things.
* If you want a copy of that prompt DM me and I'll happily share it.