ChatGPT Chatbot: looking for recommendations

We have a client who wants to implement a bot that can be used by people researching the topics covered on their site. I’ve found a handful of plug-ins when I searched (as expected), but I’m hoping someone with knowledge/experience can help me determine if there’s a particular one that would work best, or if a custom implementation will be necessary.

The bot needs to pull all of its knowledge from the site, which currently houses ~27,000 articles, and gets 50-60 new articles er week. The articles are all written in-house by human staff and are unique to the site (except for sites that steal their content…there are a lot of those). It’s not meant to be a search bot; it shouldn’t simply pull up pages with references to a question. It should formulate answers to queries based on knowledge gathered across the entire article base. Lastly, it needs to be highly configurable for presentation (unstyled + we add our own CSS is ideal). It will reside inline with navigation or in a top area search bar, not a traditional helper bot that sits in the corner.

Here’s a great example:
https://docs.gitbook.com/ – The search is at the top, and it pops open into a full chat. When you ask a question, it types its response in the same manner as ChatGPT. This isn’t necessarily how the bot will function on our client’s site, but we need that much flexibility in style, and the same “chatty” presentation.

If you have experience with these bots, or you manage a plug-in that could be configured in the manner above, please share! If not, our next step will be to evaluate doing a custom implementation, but I wanted to see if we could avoid reinventing the wheel first ??