Just to follow up for anyone reading this in future. I took the time to reinstall turbotax 2021 on another computer. After all was done, including updating, I got exact same problem...unable to print or save the "required documents" I supposedly NEED to mail to IRS as PDF.
This is a pretty big hole in this software, and as I wrote above, has been a known issue for at least 5 years.
A shame this can't be fixed or worked around.
