Even a simple hotfix can go wrong. Here is the troubleshooting matrix for 2020.2.9:
Because Revit 2020 is in legacy support, most updates now focus on cybersecurity. revit 2020.2.9 hotfix
: A major fix addresses an issue where Revit Cloud Worksharing models could not be opened due to missing metadata. Even a simple hotfix can go wrong
October 2022 Build Number: 20200915_1515(x64) revit 2020.2.9 hotfix