You could try adding objects with the date in their names to a 'backup' bucket rather than create separate buckets for each backup. S3 also supports object expi

You could try adding objects with the date in their names to a 'backup' bucket rather than create separate buckets for each backup. S3 also supports object expiration, so you can set your daily backups to expire after 7 days and weekly backups to expire after 4 weeks, for example.