Monitoring and Logging
Generally, this is done with the AWS tooling. There is information in ECS about resource usage, and further information in AWS Cloudwatch. We also log application errors to Sentry.
Please see the Monitoring page for infrastructure for specific information around this topic.
Admin App
Additionally, requests that pass through the load balancer for the Admin app are recorded in an S3 bucket.
These logs are queryable through AWS Athena, for example to find requests that resulted in a 504 response.