I knwo you can add discs via the USB port and with hub can have a fair few and can network share and backup to them. But not apple user fully and did look but found nothing to enable sync with iCloud beyond a desktop option, though may of missed something. Though did find this: https://support.apple.com/en-us/HT204618 which pertains to remote desktop and related functionality done via your iCloud account, so maybe, though still need to access via iCloud, which if just athorisation would be ok if you had a fallback option.