The Open and Universal Science (OPUS) project was implemented to drive a fundamental reform of how research and researchers are assessed within the European Research Area (ERA), promoting a shift from traditional, metric-based evaluation models toward systems that recognise, incentivise, and reward Open Science practices. Through a coordinated, evidence-based, and participatory approach, OPUS brought together research-performing and funding organisations, policy actors, and experts to co-develop practical tools and frameworks for responsible research assessment. In the framework of the activities of the second period, the project conducted a review of the comprehensive state-of-the-art analysis of global initiatives and literature, developed and tested interventions, indicators, and metrics for Open Science evaluation, and implemented them through pilot actions and mutual learning exercises across diverse institutions. Its main scientific outcomes — the OPUS Researcher Assessment Framework (RAF) and the Open Science Career Assessment Matrix 2 (OS-CAM2) — provide concrete, scalable instruments for embedding openness, collaboration, and societal value into research evaluation systems. By the end of the project, OPUS had demonstrated effective pathways for institutional and policy change, contributing significantly to the ERA’s reform agenda and to the long-term transition towards a more open, fair, and impactful research ecosystem in Europe.