And is there a chance, that this will be repaired?You're still using the wrong framing tacitly, and not exactly being subtle about it. It's a shortcoming at worst, but definitely not a defect to not provide the feature you want when it wasn't promised. There's a gap between your expectations (set for a ‘GPS smartwatch’) and what is actually offered. No defect, no repair.
There is certainly a use case for being able to answer the phone with the watch, for instance in a car while using Bluetooth it would be safer to answer from the watch than to fumble around for the phone to answer.I'd expect that if you're able to connect your phone to your car's audio system via Bluetooth, then there's most likely the facility to answer the call by a control on either the steering wheel or the front panel of the audio system. In the same way, wearing a connected Bluetooth (mic-equipped, call-compatible) headset would almost in every case provide you with a control to answer incoming calls without touching the phone.
The mute has also no effect - it only drops notification on Fenix but phone is still ringingI've just tested incoming call notifications on my Forerunner‑235, (separately) connected to up-to-date Garmin Connect Mobile apps on my:
At this time, no Garmin wearable is able to answer a phone call coming from the Android operating system.