Is your Mac set up with the same Apple ID that you used before doing your fresh install of Catalina, and are you logged into the App store with the same Apple ID?
Also, I assume you had previously downloaded & installed Pages, Numbers & Keynote to your Mac before upgrading to Catalina. Is that correct?
Note that Apple persistently updates all its own apps with every release of macOS, requiring whatever is the current version of macOS in order to install or update its apps. As of Tuesday that would be Ventura. However, the App Store is supposed to allow you to download a previous version of an app if you are on a different release of macOS. Unfortunately I have never found that to work for me.