Waze works fine for me, I connect my phone via the USB port under the heater controls. I get audio warnings from Waze that play over any radio or music that is currently playing. In the Waze settings, I have "Play sound via" set to "default device", but you can force is to play on the phone speaker or as a "bluetooth phone call". I'd mess about with these settings.
The audible speed camera alerts do only happen when you're speeding, which is annoying. They appear on the screen but no audio when you're under the speed limit. Waze has got better at understanding average speed cameras/roadworks etc and adjusting the speed limit accordingly, but it doesn't work well on the stupid/hateful "smart" motorway variable speed limits.