Adobe supports only the last two major versions of the CC App, and only they are available via the Creative Cloud Desktop app. You can follow the instructions on how to install older versions from the link below
For more older versions from 2020 and onwards, you will have to contact support and ask for a download link. They shall provide you one if they have that handly. For anything more older than that you can visit https://prodesigntools.com
This website provides download links from Adobe servers. If the links are not working then it means Adobe has discontinued providing downloads to these versions.
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