To revert back to Windows 10, please select
Open Settings followed by System and then Recovery.
Under recovery options, you’ll see the Go back option.
After a few prompts telling Microsoft why your downgrading,
you should be greeted after a reboot or two with your Windows 10 desktop.
To keep Windows on 10 and defer the upgrade until you manually upgrade can be done with the following registry entry.
Windows Registry Editor Version 5.00 [HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows\WindowsUpdate] "TargetReleaseVersion"=dword:00000001 "TargetReleaseVersionInfo"="20H2"
Below is the link to the registry entry need to stay on 20H2 and merge into the registry in Windows 10.