It sounds like you are trying to open the old tax return with the CD/Download TurboTax software, not TurboTax Online. Did you originally file it with the 2020 CD/Download software or with TurboTax Online?
If you are trying to open a .tax2020 file in the 2020 CD/Download software, and the file contains a state tax return in addition to the federal, you must install the state software before you can open the file, even if you only want to look at the federal return.
After you get the program installed or reinstalled the first thing to do before you open your tax return is to update the program and install any state programs you had. Then open your file. So you first might need to start a fake return to be able to download the state program (go to FILE - NEW). Enter some basic information, then go to the state tab and download the state program. Then try to open your existing return, go to FILE - OPEN
Error 190 for state
https://ttlc.intuit.com/community/bugs-and-error-messages/help/error-190-when-opening-file-in-turbotax-desktop/00/26443