I built a prototype along these lines as well. I was more concerned with actually giving sensitive data to ChatGPT even through their API. So it used a local LLM to scan the text first and replace sensitive info before sending on to ChatGPT. Unfortunately when i tried to interview customers to see if it was a viable product idea i got very little interest. I ended up building it into a chat app i was going to release but that’s also in limbo since ChatGPT released their desktop app. I could see these 2 things being combined, i just don’t know how big the market is for a product like that.