@Just-Lisa-Now-  "2019 you could amend, BUT nobody is processing paper returns at IRS right now, so you're out of luck with that plan too."

It would be foolish for this taxpayer to file a superseding return, but other practitioners may see a case where it should be done.  No, it's not too late.  (A Monday memo from OMB allowed agencies to “begin adjusting their operation status for a controllable, steady return to normal operations.")

https://procedurallytaxing.com/this-tax-season-may-create-many-superseding-returns/