How to access files generated by AI Assistants (Assistants API)?

Hi.

1. Our mobile app deploys assistants (create once in AI Foundry, then use assistant_id to create thread for each user @ runtime) to generate a variety of plans (PDFs) or images.
2. These files are being generated and saved in Data files sandbox: /mnt/data/<filename>
3. How do we retrieve these files from Data files using File ID? How do we access Data files location? When user requests access path or link to generated file, assistant replies with a sandbox location. However that's not a fully qualified URL that user can access publicly.
4. Solution: We may retrieve the file based on File ID and purpose = "assistant_output" -> save to a public URL and share the URL back with user to access. Would that be considered a better approach to render any type of file display?
5. Is there an easier way to access file directly from Data files (storage) and render in-app?

Appreciate help.

Thanks.