Per the Microsoft article referenced above users should upgrade to Windows 10 version 1903 or higher and Microsoft 365 version 16.011629 and higher.
That being said, this is not always possible and may not always fix this. You may be able to circumvent this by running the following in an elevated powershell:
Add-AppxPackage -register -disable c:\windows\SystemApps\Microsoft.Win32WebViewHost_cw5n1h2txyewy\AppxManifest.xml
This will reset the webview module on Windows, which should allow all these addins to work properly again.