As I speak only German, my understanding from the information on the website of
Bundespolizei is that you will be allowed entry if you can demonstrate that: i) if you intend to stay in Germany, you have held German residence status for no less than 6 months; ii) you intend to transfer to UK; iii) if you intend to transfer to another EU/EEA Member State, you hold the required documentation to complete your journey. Make sure you research carefully any applicable negative test and/or quarantine requirements.