Pages, Numbers, and Keynote v11.2 now require macOS Big Sur (11.*) as an installation requirement. The versions of these applications that you may have had on the operating system prior to Catalina would be too old to be restored to Catalina from an earlier Time Machine backup too.
What you can try, without any promise of it working, it to launch the Mac App Store while signing in with the same Apple ID as you used previously to download these applications, and then press cmd+0 (zero) to open the Purchases panel. If Pages, Numbers, and Keynote appear with an Update button, click those. It will invariably tell you that you need Big Sur installed, but it also may offer via a second dialog to install the last versions of these applications (v11.1) for Catalina.
If the second paragraph does not get you Catalina compatible versions, then you will only be able to use the iCloud or iOS/iPadOS v14.8/15.1 versions of these applications. Because, Apple does not provide user downloadable, full installers for past versions of these applications.