Can auditor sign the financials of preceding 2 years financial statements

I have been recently qualified Practicing Chartered Accountant enrolled from 02-03-2021. I have been approached by a private limited to appoint me as an auditor of the company. However, their financial statement had not been audited since financial year 2017-2018 due to the dispute with a Non-CA accounting firm (Not an Audit Firm). Please let me know

1. Whether I can audit the Financial statement for the FY 2017-2018 to 2019-2020?

2. Can an Auditor appointed during the Financial Year 2021-2022, do audit for the preceding financial years, if the same has not been done on account of the aforementioned reason?