https://www.bleepingcomputer.com/news/microsoft/how-to-download-a-windows-10-21h2-iso-from-microsoft/

Microsoft released Windows 10 21H2, the November 2021 Update, last week and you can now download an ISO image for the new version to put aside for emergencies or clean installs.

Windows 10 21H2 is not a very large feature update and only contains a few new features for business users and increased protection against WiFi side-channel attacks.