After you file

2020 is no longer supported by Turbotax so you cannot open it with the 2020 app. 

as noted you can get a transcript or copy from the IRS. 

there is also a web service - Taxprinter - unaffiliated with Turbotax/Intuit where for a fee you can send them your xxxx.tax2020 file and they can send you a copy of the return based on the file.

https://www.taxprinter.com/