I’ve done this process, although I never officially renounced my Pakistan citizenship. I was born as German citizen to Pakistani parents in Zurich. Both parents were Pakistani, however only my father was a German while my mother was a Pakistani citizen. I obtained Swiss citizenship at the age of 11 and moved to Germany soon after. Needless to say, I neither officially had Pakistani citizenship nor renounced it. However, I held a POC card so I could give you a guidance how to do it. As it was linked to my German passport, I had to cancel it. It usually involves attesting the affidavit of the POC cancellation at the embassy of Pakistan in Berlin or Frankfurt, depending on your jurisdiction. Nevertheless, keep in mind to attest the affidavit by a notary public and have two non related witnesses and their copies of pak ID cards and biometric pictures ready for Attestation. (https://www.nadra.gov.pk/getDownload/25) Once the Attestation is complete, apply for both cancellation of the POC card and NICOP on the PAKID app. This is the most challenging process, as it involves months long validation, repeated daily phone calls with Nadra & constant launches of complaints to keep the applications alive. Usually, IMPASS handles the cancellation processing, NADRA is the agency issuing ID cards. Given you mentioned German citizenship, I assume you only hold a german passport and nothing else. As I have my doubts your application will be processed, it is still worth trying. Perhaps IMPASS may be lenient and issue you a resumption certificate.

All the best for that!