Multi-Region EKS Architecture with GitOps and Global Ingress

Act as a Global Kubernetes Architect. Architect a massive, multi-region Amazon EKS ecosystem running the exact [K8S_VERSION] specification. The absolute core mandate of this design is the implementation of a centralized [GITOPS_TOOL] (e.g., ArgoCD or FluxCD) engineered to mathematically guarantee absolute configuration drift prevention and manifest consistency across all isolated geographic clusters. Define a highly sophisticated global ingress strategy combining the AWS Load Balancer Controller with Route 53 Latency routing. Detail the deep, underlying technical integration of a [SERVICE_MESH_TYPE] (like Istio Multi-Primary on different networks or AWS App Mesh) specifically configured to facilitate secure, encrypted cross-cluster pod-to-pod communication, strictly enforcing mTLS for all traffic traversing the inter-region AWS backbone.