Can I Downloading all S3 objects

Not sure what the use case is and how many objects etc. are there. Having said that, one option aws s3 sync can help.

Reference : https://awscli.amazonaws.com/v2/documentation/api/latest/reference/s3/sync.html

Syncs directories and S3 prefixes. Recursively copies new and updated files from the source directory to the destination. Only creates folders in the destination if they contain one or more files.