Yes, Sydney can be considered a German name, although it is more commonly associated with English origins. The name derives from an Old French place name, which in turn comes from the Germanic elements meaning "wide island" or "sandy island." While it is predominantly used in English-speaking countries, it may also appear in German-speaking regions, though it is less common.
Sydney is Sydney.
Sydney Henegar is spelled the same in German as it is in English
Sydney's name is just Sydney. It's not spelled differently..
Sydney Fairbrother's birth name is Sydney Tapping.
Just like you do in English
Sydney Pollack's birth name is Sydney Irwin Pollack.
Sydney Newman's birth name is Sydney Cecil Newman.
Sydney Sidner's birth name is Kathryn Sydney Sidner.
Robin Sydney's birth name is Robin Sydney Heymsfield.
Sydney Spies's birth name is Sydney Elizabeth Spies.
Sydney Streeter's birth name is Sydney Stanley Streeter.
Sydney Penny's birth name is Sydney Margaret Penny.