If you are running Android <11 then apps could see the list of apps installed on the device developer.android.com/…/package-visibility

Pure speculation (and how I would do it) is to have apps A, B, C check periodically the list of installed packages and if one of them disappeared from the list I would trigger this survey. Of course that requires that all apps are from the same developer, and it won’t trigger this survey on the last app uninstall