Edge 705
I’ve got a Garmin Edge 705 which will give full turn by turn navigation on the bike along with every concievable bike computer function. It works really well once you’ve mastered how to use it, Garmin’s documentation does nothing whatsoever to assist in that!
Creating a route in bike route toaster and transfering it as a GPX file to the 705 will give full turn notification along with the name of the road your turning into etc.