I have not yet received my 2019 tax return, as I am waiting for a response from the IRS after receiving CP05A notice. Should I file my 2020 taxes?

Got CP05A notice for 2019 refund back in November, provided the required information in December but have still not received refund. Apart from contacting the IRS about the 2019 return (am actively trying, but their lines are constantly busy), should I continue with my 2020 taxes or wait until I hear back about my 2019 return.