iPhone 14 pro in installments

I am non-German, living in Germany. I want to buy iPhone 14 pro in 24 months installments. However during identification check, only German passport or ID card is expected. I hold a permanent residence, however the document is not valid.

I would like to know whether the 24 month installment scheme is only valid for German citizens in Germany? If not it would be great if you can help me sort out the issue with the same.