Your approach to scaling the Outbox processor from a basic implementation to handling billions of messages daily is incredibly detailed and practical. The breakdown of each optimization, from query indexing to parallel processing and RabbitMQ batch publishing, provides a clear path to boost throughput in high-demand systems. The insights on trade-offs, such as message ordering and publisher confirmation, highlight important considerations for balancing reliability and performance. Adding examples for handling consumer backlogs in high-throughput scenarios could add further depth. Thanks for this comprehensive guide!