As organisations scale data processing to petabyte levels, reliance on hyperscaler-managed services often creates data residency risks. In this session, I will demonstrate how to architect high-scale data processing pipelines using Argo Workflows on sovereign infrastructure. We will cover architectural patterns for decoupling storage from compute, managing ephemeral processing nodes without vendor lock-in, and ensuring that sensitive data never leaves your sovereign boundary during transformation. Attendees will leave with a blueprint for building performant, compliant, and completely independent data platforms.