Hello,
Thank you for posting in Microsoft Community forum.
Based on the description, I understand your question is related to update.
Seems the CBS missing/ corruption points to KB4507459, it is a very old update released on July 16, 2019.
July 16, 2019—KB4507459 (OS Build 14393.3115) - Microsoft Support
Unfortunately, I checked the windows update catalog and seems this update is too old so it is retied. Maybe manually fix by using this update package is not available right now.
Based on current situation, it is recommended to do in place upgrade to help fix CBS. You can use the same version ISO which is Server 2016 Std to do the operation, and dDuring the upgrade, Select Keep personal files and apps
How to do an in-place upgrade - Windows Server | Microsoft Learn
Note: For the sake of double security, it is recommended that you back up your important data first to prevent unknown issue during the upgrade.
Have a nice day.
Best Regards,
Molly