On your first question about the timeout issue, you can try using the ChatGPT API directly in the HTTP module. There you can set the timeout limit up to 300 seconds.
On your second question: You can use the datastore to store some predefined guideline and map it with the prompt, so you don’t have to feed it every time manually.
Refer here: https://www.make.com/en/help/tools/data-store.