Not sure what you mean by "upload" ... the program only "imports" information and the program doesn't guarantee any imported information ... this is something you need to review and correct if needed before you file. Your only option now is to amend the return to correct the error and pay any balance due asap to reduce any penalties or interest.
Now just a note ... the program can only import what is available for importing from the issuer. The issuer usually has a time deadline for importing ... usually between Jan and Oct for the current tax season so I am not sure how a 2020 W-2 could have been imported to a 2021 return ... it should not be possible.
