Naturalisation and EU settled status

Hi everyone

I thought I'd post my question here since it's related. I'm an EU citizen and I've held a document certifying permanent residence since 2018. I haven't applied for the Settled status scheme yet because my plan was to apply for British citizenship using my PR document by the end of this year, however, due to the absences criteria, I realized it's best to wait till February next year to send my BC application. My questions are:
1. Will I still be able to use my PR document to apply for BC next year, or does it cease to be valid on the 31st December 2020?
2. If I apply for The EU settlement scheme now, can I still use PR document to apply for BC, or would I then need to wait 1 year from the date of EUSS grant to then apply for BC through that route?
3.If I apply for the EU settlement scheme next year, will I be able to use my PR document in that application to be granted Settled Status automatically, or do I need to do that this year if I want to use the PR?

Hope the questions are clear. I appreciate your support!