Scenic Phase 2 starter defective?

Hello together, our Scenic (Automatic, 1.6, 107hp) no longer makes a sound when turning the key. Since I thought recently to hear a cumbersome turning of the engine when starting, I thought – because car outside and temperatures at -5 degrees – immediately to the battery. The battery has a viewing window and showed fine, I then installed the charger and after 5 hours showed the device full. When turning the key however (except for the petrol pump) nothing happens at all, also the e Lighting in the interior doesn’t get darker or even collapses, so I would close on a defective battery. I have added a bridge to another battery, didn’t help either. A new starter was installed in 2018 with the workshop notice “Dental wreath worn, splint may be broken soon”. That can’t be the trigger for a new defect of the starter now, can it? how would you proceed so that I can rule out the simplest things and maybe there were problems with the ignition lock? I would be very grateful about tips! Greetings Micha