Using your aia project (with some adjustments - filescope to App and remove the tinydb blocks) the url downloads the file to my device. So no intrinsic issue with the url.
Since you have set DefaultFileScope = Legacy, the path (.ResponseFileName) on Android 11+ must be set to one of the Shared folders (/Download, /Music etc).
That depends on what exactly you want to do. If the file(s) should also be available on Android 11+ in a visible area (directory such as /Music, /Download, Documents,...), DefaultFileScope=Legacy or Shared must be set.
Is it a difference between iOS and Android? Or due to App Inventor implementation of the web component?
In any case, would be great to keep the original file name with ANdroid App
Yes, this is a way to specify the file name. But the app has to know the file name! I was planning to provide only the link to the App, so it does know the file name of the downloaded file.
iOS is able to retreive it from the link! Any reason Android or Web component of App inventor cannot do it?
Otherwise, as uggested by @TIMAI2 it may be possible to use some Google drive API to get this information.