Amazon PPC advertising campaign in Germany

We are an online company selling stress relief toys, (mainly stress balls) through Amazon. We sell in the UK and Germany. We need to improve our advretising campaign in Germany as our ACOS is high.
We need a German national to help with the improving our PPC campaigns as the person will need to understand fluently the German nuances for key words and phrases.
The work would be ongoing with reviewing on a monthly basis