Many (in fact I would bet most) other AWS services themselves use DynamoDB under the hood for various control-plane and data-plane uses-cases. It is not unimaginable that the actual traffic to DynamoDB service in total at regular daily peaks would be in the nine or ten digits per second.
Granted, these are across different AWS accounts, across different tables but still delivered by a single logical service.
Apples to oranges to be sure but >100x this scale for a single tenant of a multi-tenant database system is super impressive, too!
https://aws.amazon.com/blogs/aws/amazon-prime-day-2022-aws-f...