Having the Quick answer feature link up to the Assistant, so that they're the same underlying models, but the quick answer is easier to access. When pressed, it would respond like Fast or Expert would (changeable in settings), and you could press a button to continue in the Assistant interface.
Instead of (or maybe keeping, whichever is best), have an AI Answer button:
Then have a Follow Up Question button of some sorts like:
That would lead into the Assistant Interface where the answer and question should be the same.
Another way to do it would be like NEW BING's way of doing it:
