You are right, we were thinking of something along the lines of files expiring after a certain age. I am not sure if automating the deletion via a script would be possible in our case. The tool that would generate the temporary file would be run by users with varying credentials, and the files would be created in Collabs of which they are members (this is necessary here for privacy and access concerns). So no single user account would have access, or even be aware, of the relevant Collab that needs to be scanned.
But good to know that such a feature isn't expected soon. We could maybe embed such a script within the tool itself, such that for each subsequent usage by a user, their older files are checked and deleted. Thanks!