You also will pay for data transfer to download your backed up data when recovering. The key insight is that it makes sense to use a large EC2 instance to download and transfer your Takeout data, rather than your home internet. So, the only billable aspects of this setup are the EC2 instance cost while copying the backup, long-term S3 storage fees (which we already established are quite low), and charges for data egress if/when you need to download your backup.