export phone data to USB medium

I've been having issues with data backed up from an S-10 to FAT formatted USB sticks. These (4 or 5 now) become to various extents unusable following. Still investigating and I don't have all the info but there seems to be a problem. The file system became read-only in sone cases, in others the media become unrecognizable in assorted COMPUTER OSes for unknown reasons. Samsung or android throw an alert when the backup begins about some Samsung account password becoming required to 'restore' from such data, which is ok when using the media to recover from, but under no other circustance. At a minimum it seems to me that there is a need to include in the backup menu a RAW-DATA ONLY EXPORT (image, movie, document, whatever data files) all of which of course should output read-write-by-all to any known filesystem.