Η Microsoft released the official ISO images for Windows 10 version 21H2 for Insiders (build 19044.1202). The same version is currently also available in Release Preview channel. So now you can download the ISO you are interested in and make a clean one installation of the latest version of Windows 10.
Release Preview versions are fairly stable. Although it is a pre-release version, it has changes compared to the current "fixed" version. As with 20H2 and 21H1, the new 21H2 will be a small cumulative update for Windows 10 2004 with a few minor tweaks. All of the aforementioned versions of Windows 10 share the same code base.
Thus, Windows 10 of version 21H2 is based on the same code as versions 2004, 20H2 and 21H1. In addition, all changes from 20H2, 21H1 and 21H2 were added to the 2004 version with cumulative updates. They are just hidden and need to be activated with one packet "Activation". So it is very likely that the upgrade to version 21H2 at this time will not affect the user experience.
To download the ISO you are interested in, sign in with your Microsoft Account and Insider Program from here.
Select build "19044.1202" from the list of available versions.
Select the desired language, e.g. Greek and confirm your choice.
Then you can download it archive ISO in 32 or 64-bit.