So: Unpacked, and 1x checked with the WD tools on PC. in the WD tools can be the standby time (10 min) to configure.
Now the attempt on Technisat. Rear USB port: HDD is not detected. At the front connector at the 2nd attempt.
Since I've had similar problems with the previous HDD (Toshiba), I swapped out the USB cable.
Behold now they went. And yes, after 10 minutes. Inactivity (even in Quick Start mode) it will shut down.
Conclusion: the Technisat has strange USB ports, which can not be fully Plug USB 3 connector
After the replacement of the cable, the HDD is working properly and is not audible.