Citizenship Verification Wait and US Passport Resubmission

Just found this sub, and thought I would ask some burning questions I had here. I applied for my verification of citizenship based on my German Father after being directed by Houston to do so after some back and forth emails. I applied in January and got my case number in July. How long am I truly looking at till I get a result? Does it really take up to 3 years, I have been reading that and not sure if it’s true. If it is, that is crazy.

Also, my US Passport Book has expired and that was the photocopy I sent to Germany via the consulate. I am right now waiting on my renewal, and wondering if I have to send a certified photocopy of the new one to the case worker in Köln or does it not matter?

I also plan to go to Frankfurt to see relatives and want to make sure I wont have any issues with the Bundespolizei at the airport at immigration because of my application. Any advice is appreciated. Thanks.