S3 BytesUploaded, BytesDownloaded metrics are not recorded in CloudWatch

Hello! You need to opt in to request metrics in the console, via the REST API, or via the AWS CLI. To opt in to request metrics for S3 using the console, you need to do the following:

1. Sign in to the AWS Management Console and open the Amazon S3 console.
2. In the Buckets list, choose the name of the bucket that contains the objects you want request metrics for.
3. Choose the Metrics tab.
4. Under Bucket metrics, choose View additional charts.
5. Choose the Request metrics tab.
6. Choose Create filter.
7. In the Filter name box, enter your filter name. NOTE: Names can only contain letters, numbers, periods, dashes, and underscores. We recommend using the name EntireBucket for a filter that applies to all objects.
8. Under Filter scope, choose This filter applies to all objects in the bucket. (You can also define a filter so that the metrics are only collected and reported on a subset of objects in the bucket. For more information, see Creating a metrics configuration that filters by prefix, object tag, or access point.)
9. Choose Save changes.
10. On the Request metrics tab, under Filters, choose the filter that you just created.
11. After about 15 minutes, CloudWatch begins tracking these request metrics. You can see them on the Request metrics tab. You can see graphs for the metrics on the Amazon S3 or CloudWatch console.

For more information or alternative ways of opting in via the REST API or AWS CLI, see Creating a CloudWatch metrics configuration for all the objects in your bucket. It's also helpful to be aware of the CloudWatch metrics configurations and considerations.

Hope this helps!