Q. Where will I find the Tech Bench ISO?

Answer.

The Tech Bench page has been renamed to Windows 10 ISO:

https://www.microsoft.com/en-us/software-download/windows10ISO/

EDIT: Depending on your browser/Windows version, you may have to trick the website into believing that you can’t run the media creation tool on your system, to get the “You’ve been routed to this page because the operating system you’re using won’t support the Windows 10 media creation tool (…)” text (instead of a redirect to the media creation tool download) and therefore be able to select an ISO download.