Can a .tax2021 turbotax file be printed or converted to a pdf without the 2021 turbotax software? I have the 2020 turbotax software installation file available.

A tax data file, which has a file extension of .taxyyyy, where yyyy is the tax year, eg .tax2021 for tax year 2021 can only be opened by the TurboTax software for the year of the tax data file.  There is no conversion procedure to convert a tax data file to a PDF.

If you navigate to the directory where the 2021 tax return is saved,  look for a file name ending with ".tax2021". Look at the icon before the name, if it has a red checkmark it means that the 2021 software is installed on your computer. If the red checkmark is not present unfortunately you will need to reinstall the 2021 TurboTax software. 

After you successfully open the ".tax2021" tax return you should be able to print it and save it as a PDF file.

there is an outside service that can convert your .tax2021 file to a pdf

https://www.taxprinter.com/