How can I assign keys on the huawei mate 20?

Would the loud key assign a quick activation of the voice recorder. 2x pressed down quietly activates the camera.

Under which option point can I do that?

I'm sorry to disappoint you but unfortunately there's no attitude. The Ultraschnappschuss is a setting that can be set on the camera and turn off.

The only thing I can advise you to look for an app, but can't promise you anything.