Hello,
Thank you for posting in Microsoft Community forum.
Based on the description, I understand your question is related to update KB5005568.
This is a very old update released on Sept.14,2021, if it cannot be found in update catalog, it might be retired: September 14, 2021—KB5005568 (OS Build 17763.2183) - Microsoft Support
Because windows update are cumulative, which means the newly released monthly updates will contain the contents of the previous ones. So, there is no need to install the Sept.14,2021 KB5005568 separately, you can install any new windows monthly update for Server 2019 released after that date, which will contain the contents of KB5005568.
For example, the latest windows update for Server 2019 is KB5044277:
October 8, 2024—KB5044277 (OS Build 17763.6414) - Microsoft Support
Have a nice day.
Best Regards,
Molly