Are there any special requirements to enter Germany besides my ID card, passport and orders?

Yes. As of Nov. 8, 2020 travelers seeking entry into Germany who have been in a risk area (which includes the US) in the last 10 days are required to complete Germany’s Digital Registration on Entry and provide proof of registration when entering the country. Visit the Federal Ministry of Health’s FAQ site for more details in English.

Source: https://www.europeafrica.army.mil/coronavirus/