I forgot to bookmark my resource for allowing users to download file contents from the attachments column.
Launch($"{frm_envurl}api/data/v9.2/fccbh_documentattachments({ThisItem.'Document Attachment'})/fccbh_attach_file/$value");
Using this, I'm able to download the files from the record but my end users are not able to even if they uploaded the files. I believe this is a function of the web Api, but I'm not sure where the permissions are managed.