This research paper analyzes Austrian companies' supply chain connections to extractive activities and/in the Global South within the context of the EU Corporate Sustainability Due Diligence Directive (CSDDD). The EU CSDDD requires businesses to identify and address environmental and human rights risks throughout their global operations, but faces political attempts to weaken its implementation. Chief among what is termed the Omnibus simplification package is the proposal to limit due diligence obligations to first-tier suppliers only, effectively allowing companies to ignore potential environmental and human rights violations occurring deeper in their supply chains – precisely where the most severe risks often exist. Our contribution demonstrates that comprehensive supply chain mapping beyond first-tier suppliers is both necessary and feasible using existing commercial datasets. Our illustrative case studies of Austrian companies provide regulators, advocacy groups and social movements with theoretically guided insights into the possibilities and challenges of driving meaningful upgrading of environmental and labor standards throughout global production networks. Building on existing GVC and GPN analysis, we argue that our approach can offer useful pointers on where initiatives such as the CSDDD can be most impactful, and how public governance can strengthen private and social governance so that due diligence becomes a robust, globally just and context-sensitive instrument for sustainability transformation.