Debug the full stack end to end (Go runtime, OS, network, datastores, Kubernetes, cloud) to root-cause bottlenecks and regressions such as goroutine leaks, lock and channel contention, GC pressure, connection pool exhaustion, TCP/TLS behavior, API rate limiting, and slow queries. Design and run performance and scalability tests for connectors and ingestion pipelines (throughput, latency, concurrency, soak), with dataset generators that reproduce realistic source data shapes, object counts, payload sizes, and change rates.