From January 1st, you can only use your PR card if you haven't been granted settled status

In order to apply for citizenship, applicants must have ILR, including Settled Status.

The application submission date is the relevant date for ALL practical purposes, not the biometrics appointment date.

If you have settled status, you CAN NO LONGER apply with a PR card.

Citizenship chart
Step-by-step guide

Please refer to the following resources:

PR, ILR and Settled Status
Language requirement
Life in the UK
The Residence Requirement
Absences
Lawful residence
Good Character
Referees
Evidence of residence
Filling in the AN form
UKVCAS