One thing to note is that we support almost exactly what I’d being described here in chat with threads. There’s an option to have AI automatically title chat threads:
We do use this in our internal forum. The titles themselves are not always in your face, but people do see them in certain views, and they prove helpful in the “my threads” view, or the view that lists all the threads in a given channel. They are also quite humorous sometimes, and the stakes of them being “wrong” feel a lot lower than if they were used for topic titles themselves.
I understand it’s not what you want here, but tinkering with it may be illuminating and inform your thinking about what you are looking for here.