User reports error code 0xc1900223 when trying to update Windows 10 to version 21H2 using Windows Update Tool.

Download the Media Creation Tool for Win 10 21H2 Update: https://go.microsoft.com/fwlink/?LinkId=691209

When download is finished open the tool,
Accept licence terms,
Select the "Upgrade this PC now" option to start the update.

Click "Next", the program will run downloading any updates needed to get the system ready for the version update then will install the version update and reboot.
Once complete check the patch history to ensure the version is now 21H2.

If this is unsuccessful there are other steps that can be taken using this link: https://www.yourwindowsguide.com/2021/11/install-windows-10-version-21h2-offline.html