This isn't how central banks value their fiat currency.
If for some reason the Fed puts 20% interest on the USD, the value of the USD would increase dramatically. The Euro is under no obligation to set its value with respect to the USD or the Pound.
There is no "intended" value of the Euro with respect to other currencies.
There's an "intended" value of the Euro with respect to keeping European governments solvent and keeping prices steadily increasing.
If the Euro has to drop to $0.01 to achieve those goals, it will. If it has to climb to $100 to achieve those goals, it will.