Help - confused re BRP

I have found some very useful information on this site but I remain confused. I am hoping someone will be able to help.

I received a Permanent Residence Card sticker in my passport in 2013 which expires in 2023 (Married to German citizen) however my passport (South African) has since expired - do I need to apply for a BRP card before I apply for citizenship? I know from this site that you can still apply with an expired passport but I am just confused with the whole BRP - is my sticker and the BRP one and the same? I can't remember if when I applied for the permanent res. card if I gave biometric details?

I have considered going to an immigration lawyer but they are quoting astronomical prices - so if anyone knows a firm in the Peterborough area and their fees are fair and reasonable that would also be helpful.

Thank you!

No you don't need a biometric residence card to apply for citizenship.