The July KB5101650 update is being reported as causing some problems, some PC's will not boot up after the update, other users are reporting the keyboard does not work after that update, the problem with the Windows key is not yet a reported problem in that update.
If uninstalling the update does resolve the problem with the Windows Key and Windows button on the Taskbar, it may be best to uninstall the update and pause your updates to stop that update reinstalling on your system.
If the update has reinstalled and you are unable to uninstall the update, open the Settings App.
Go to System - Recovery.
Click the 'Reinstall Now' button in the 'Fix problems with Windows Updates' section and wait for that process to complete.