If you already have Windows Server 2019 installed and only need the specific files to reach build 17763.1817, you can download the standalone update package:
Windows Server 2019 build corresponds specifically to the cumulative security update KB5000822 , released on March 9, 2021 . Download File Windows Server 2019 [17763.1817] ...
Microsoft provides a 180-day evaluation version of Windows Server 2019. While the Microsoft Evaluation Center typically offers the most recent refreshed ISO (often build 17763.737), you can reach build 17763.1817 by installing the base ISO and then applying the update through Windows Update. Editions available: Datacenter and Standard. If you already have Windows Server 2019 installed