Applying for determination of German citizenship (Feststellung der deutschen Staatsangehörigkeit) by ancestry is normally done, by individuals not living in Germany, through their local consulate, who forwards the application to the German "Federal Office of Administration" (Bundesverwaltungsamt, BVA).
The BVA's website says: "The BVA is the competent authority with respect to naturalization as a German national and the establishment of German citizenship for people living abroad."
Unfortunately the application processing time when applying through a consulate/the BVA is currently quoted as 2-3 years.
It is also possible to apply for determination of citizenship at local offices in each German city. I suspect this option requires one to be a registered resident of the corresponding city/district. Is that true?
Is it feasible, as someone who does not currently live in Germany, to apply via one of the local offices? What would be required?
What is the processing time when applying through a local office? Is it the same 2-3 years as via the BVA? Or is it much shorter?