Hi there,
Is this only with security updates and are all updates installing automatically?
If you have any third-party antivirus the Defender will not work even when updates are installed .
So if this is with all updates try enabling the Update service again and run the SFC & DISM scans.
Try resetting the Update components
https://learn.microsoft.com/en-gb/windows/deployment/update/windows-update-resources
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