I wound up spending 2 1/2 hours with a wonderful woman from TurboTax support. I’d tried the uninstall, but couldn’t find the TurboTax extensions mentioned in the article on how to fix. I’d been entering /Library in the Finder window, not ~/Library. It turns out that the “~” was really important to finding those files and deleting them. Now my TurboTax 2020 works on Mac Big Sur 11.2, thank goodness. But like other posters have noted, I still get the “error - report this to TurboTax” pop up - now I know to decline and not hit “send to TurboTax”, and I can use the application without further problems.
