Blocking KB5005463

This is needed, see here why.

reg add HKLM\SOFTWARE\Microsoft\PCHealthCheck /f /v installed /t REG_DWORD /d 1

Blocking the Update offers and setting the base target

reg add HKLM\SOFTWARE\Policies\Microsoft\Windows\WindowsUpdate /f /v TargetReleaseVersion /t REG_DWORD /d 1

reg add HKLM\SOFTWARE\Policies\Microsoft\Windows\WindowsUpdate /f /v TargetReleaseVersionInfo /t REG_SZ /d 21H2

Block the Windows 11 Upgrade via GPO

• Click Start, and then click Run.
• Type gpedit.msc, and then click Ok.
• Computer Configuration > Administrative Templates > Windows Components > Windows Update > Manage end user experience
• Double click on Configure Automatic Updates.
• Select Disabled.