+1 on this. I upvoted the original comment but I don't see any official way to upvote the idea or vote for it.
I can/will say that I think the AI sidebar should be able to be configured to connect to any LLMGAI that exposes an API supporting a standard interface.
Thank you @Jbyr - it's a reasonable workaround (and I will use it!) But doesn't negate the need for more official support. Sending text to the chatbot doesn't work correctly for instance.
I used duck.ai in the url section and on my mac use the CTRL+X keyboard shortcut to enable the chat. May you may have to enable that but the URL part works.