Novel writing and addressing the limits of ChatGPT

I try to use ChatGPT for novel writing and try to overcome some of its limits.
While I know that I have to provide all the context, there a certain aspects that might be bugs. And if it is my limited understanding of ChatGPT, I am thankful for every hint.

OK, so to start:
I am using GPT4 with Advanced Data Analysis.
I have prepared files that describe characters, locations etc.

I have at the moment one chat per chapter.
But when the chat is getting longer ChatGPT seems to forget about things set up at the beginning of the chat.
Is that normal behaviour?
How do I know when something I built my story on falls out of the context window?

The other thing is, that it seems that the longer a chat for a chapter gets, the more buggy the chat gets.

E.g.: It didn’t remember a character.
So I provided the file again as an upload.
It still got the character wrong.
I told ChatGPT to read the uploaded file.
It agreed and still described the character wrong.

If anyone has best practices to set up ChatGPT for novel writing with actively knowing the limits and save ways to circumvent them: Please drop me a note.

I’m using copilot to write a novel, and if it forgets, i usually copy and paste the previous chapter to refresh it’s memory, my chapters usually don’t exceed 3000 characters, and the copilot creative max character count is 4000. im also doing short melodies to go along with the chapters, because the main character is a bard, and that seems to be increasingly helpful due to them having less characters, i can paste more at a time. (do keep in mind, i am using the windows 11 desktop copilot.) hope this helps!
-G