the nicest route to cycle from London Berlin within reason?

The EuroVelo 7 (EV7) also called the "Sun Route" is the longest of all the EuroVelo routes, approximately 7.409 kilometers long. It originates in Norway, passes through Norway, Sweden, Denmark, Germany, the Czech Republic, Austria, Hungary, Serbia, Bulgaria, and Greece, and ends on the island of Cyprus. The route also serves various historic, cultural, and natural tourist destinations.