Did you buy the ddpai m6 in the end? I thought I would update that I'm quite happy with mine. It is discrete without a screen, and easy to detach from the mount, (magnet) if needs be.
Other than the window adhesive pad, there's no real install work. The power wire fit between the windscreen and headlining with ease.
Setup is easy via a mobile phone. The recordings can be viewed via mobile phone or by taking the memory card out of the camera.
The only thing I hate is the power ok greeting, which I cannot turn off. Rather odd to be greeted by a Chinese voice saying D-d-pia-hello.