ColdFusion 2021 silent install zip file

Well, let me clarify first that the silent install capability is offered with EITHER the zip install approach (which is new to CF2021) or the traditional "full install" files (such as with that exe, on Windows) which have always existed.

Second, you're right that that downloads page offers full installers (exe for Windows, .bin for Linux, etc.) and does NOT offer the zip files. While it's new that those full installers are offered there (they are "refreshed" installers including update 5, as I discuss in a blog post), it's NOT  really new that the page doesn't offer the zips.

To be clear, normally one can get the zip or full installer from the page where you obtain a "trial" of CF (the same files work whether one is running a trial, or will put in a license key, or will use the free Developer edition). As you'll see there, you do need to fill out the form (and login, if you have not logged in before), and then at the bottom of the form is a select control where you would choose to get the zip (or full) install file.

Finally, if you'd not yet found it, note that the docs discuss using the silent install with the zip approach (and the cfinstall.bat or sh) one would need to run after extracting the zip.