A new script makes it easy to create an ISO for any version of Windows 10, including Windows 10 version 1507 through 20H2. The script downloads the associated Windows 10 Media Creation Tool and other support files and automatically launches the program in Windows 10. This ISO file can then be written, or burned, to a DVD to create a replica of the original media, mounted as a drive letter in Windows, or extracted by a program like 7-Zip to access the contained files. If you want to perform a clean install or run into a problem, it is always helpful to download an ISO that can be used to create Windows 10 media.
Source: https://www.bleepingcomputer.com/news/microsoft/download-isos-for-any-version-of-windows-10-with-this-script/