AWS Backup Job doesn't show backup size for FSx

The AWS Backup service doesn't directly provide information about the size of daily backups for Amazon FSx in the AWS Management Console or through the describe-backup-job API call. The BackupSizeInBytes and BytesTransferred fields returned by describe-backup-job may not be accurate or populated for certain types of resources, and they might not reflect the actual size of the backup for Amazon FSx :- https://docs.aws.amazon.com/aws-backup/latest/devguide/whatisbackup.html

These are the alternatives you can use AWS Backup publishes CloudWatch metrics related to backup jobs. You can use CloudWatch Alarms to create alerts based on these metrics. Metrics related to backup sizes include: BackupStorageSizeBytes ,RestoreDiskSizeBytes and RestoreObjectSizeBytes for example, you can create a CloudWatch Alarm to alert you when the BackupStorageSizeBytes metric exceeds a certain threshold, indicating a significant increase in backup storage size also you can Create an AWS Lambda function that gets triggered by CloudWatch Events for completed backup jobs. The Lambda function can use the describe-backup-job API call to gather information about the backup job, including the size, and then log or store this information in a central location.

Hope it clarifies and if does I would appreciate answer to be accepted so that community can benefit for clarity, thanks ;)