If you are using MSP360 Managed Backup you can use the Backup Storage tab in the management console and Quick Restore application to browse and restore individual files and folders - https://help.mspbackups.com/restore/quick-restore

This is also available in the backup agent

yes MSP restore works to be able to search and restore individual files

However I require that someone else logs in on his computer and downloads the native backed up file directly from AWS S3 Bucket

He does not have MSP360 on his system

This used to be possiblle in the older version

With the legacy format, it was possible, but the New Backup Format only handles archives. Plus, there's this neat feature called Online Access. It lets you get into the Backup Storage tab without needing full console access or any extra software. https://help.mspbackups.com/organization/settings/online-access