Hi @Stefano5C37,
Only the latest two versions of the Creative Cloud apps are supported and available for download so you will only be able to download 2023 and 2022 using the Creative Cloud application. For 2021 version you would have to contact Adobe support and ask for installers, they will provide one if that is available
To contact support follow the instructions given below
1. Go to https://helpx.adobe.com/contact.html?rghtup=autoOpen
2. Wait a bit on the page that opens up, it should automatically open a chat popup. If that does not happen then look for a call out/chat icon at the bottom right, click over it and the chat popup should open
3. In order to talk to a human type "AGENT" in the chat box
4. If you are not able to get to the chat window, then disable your adblockers, firewall, enable cookies/scripts on your browser. If it still fails then change your browser/machine/network.
P.S. Be mindful of answering anyone who sends you a private message. See the following for more information about scammers
https://tinyurl.com/y7cfrr7y
-Manan