https://wccftech.com/windows-10-iso-files-available-for-20h2-build-19042-and-build-20201/

Microsoft has released the Windows 10 ISO files for the Preview Build 20201 that was released earlier today by the Windows maker. Delivered to the Dev Channel, the current builds aren't tied to any specific future version of the operating system, however, are likely to be part of the 2021 releases.

ISO files are also available for Windows 10 20H2 Build 19042. For Insiders in the Dev and Beta Channels testing Windows 10 2021 and 20H2 features, respectively, you can now clean install the latest Builds 20201 and 19042 through the ISO files.