The File component uses/requires a relative path if the FileScope is "Shared" or "Legacy". If the FileScope = App, ONLY the filename is needed to store the file in the ASD (that means the file will be automatically redirected to the ASD). However, the ASD is no longer visible on devices running Android 11+. Also, as @Taifun said, other apps can't access your app's ASD.
So if the file needs to be viewable from the device, you need to save the file on Android 11+ devices in one of the Shared folders (/Download or /Documents) in order for this file to be viewable. However, only your app has access to this file. Otherwise you must use SAF. However, the latter requires that the file was saved in the Shared folder /Documents, since the /Download directory is not accessible (cannot be selected) with SAF.
See also here: