Thanks for your replies

I'm not a lawyer but from my point of view we are in a gray area. It's not allowed to use device with the single use of detecting speed traps or stop-and-search operation.

If you will be stoped by the police you should turn of your screen. You don't have to turn on screen on police request.

Waze blocked this function for a long time in DACH and France because they thought it's illegal. Germany got this function back after hard discussions.

Definitely not illegal.
But it's illegal to hold the Smartphone in your Hand while driving. Use a Smartphone Car Holder.
It's legal limbo to tap on the Screen while driving. Better don't do it while Police is near to you - even if you are at a traffic light.
About the reporting of Police - I don't have a clue. Never heard of it, that it's illegal in Germany but I would be suprised if they are looking for Waze
Also the SpeedCams are legal limbo. In Switzerland they are forbidden so even in Waze they deleted them and also disabled the function to report some.

Mynios was quicker... Yes, you can turn off your screen and don't need to turn it on again.

If I'm not wrong you can also disable the SpeedCams in the App. I think everyone is using it but if you feel uncomfortable, disable it.