Chaos Engineering (CE) and Software Performance Engineering (SPE) are increasingly important for validating the resilience and performance of cloud-native microservice systems. Yet, existing CE tools remain limited by environment-specific assumptions, narrow fault models, or substantial manual integration with load testing, resulting in high overhead, a high required level of technical expertise, and low reproducibility. To address these shortcomings, we present CERES, a system-independent and infrastructure-agnostic framework that unifies configurable chaos injection, structured workload generation, and automated observability in a coordinated experimentation workflow. While the tool is independent of any specific system under test, we complement it with MiSArch, a realistic microservice reference architecture that enables reproducible evaluations and supports research on architectural resilience. We evaluate the tool through a usability study with researchers and industry engineers, as well as through empirical experiments using MiSArch that explore performance limits under varying load and failure scenarios and allow the derivation of initial service-level objective boundaries. The results demonstrate that the tool substantially reduces the effort required to design, execute, and analyze combined CE and SPE experiments. Researchers and DevOps engineers benefit from a reusable, accessible, and system-independent experimentation framework that lowers the barrier to systematic and reproducible resilience assessments.