How to find AI models for various niches?

I am looking at the financial/stock market niche. How would you go about finding an AI model to use for an AI app for it?

For example, if I were to scrape hundreds of reports about various stocks and feed them to chatgpt to get predictions and analysis, I think it would lose it after a bit (I noticed chatgpt works better with smaller queries), so how and where you find various models for various tasks? Can someone explain this like like to a 5 year old in as plain language as possible?

Thank you!