Apple Watch Series 9 Crackling Calls and Notification Drops Despite Multiple Replacements

I purchased the Apple Watch Series 9 (45 mm) from MediaMarkt. From the very first day, I have been experiencing constant crackling during phone calls and frequent notification dropouts. This issue occurs in every call and under every condition.

To resolve the problem, I contacted both Apple and MediaMarkt technical service. Each time, a new replacement device was provided, yet the exact same issue continued with every unit. My product is still under warranty, and I have all related documents.

At this point, I am requesting a permanent solution. I want Apple to address this ongoing problem and resolve the situation so that I am no longer affected by this repeated issue.