A presentation materials from Global Summit on Diamond Open Access in UAEMex, Toluca, Mexico. Website: https://globaldiamantoa.org/en/home-2/ OCTOBER 23 - 27, 2023 Highlights: Adaptation through Top-Down Systems: Tanzil highlighted the Indonesian experience where a top-down approach played a crucial role in acclimating society to new ecosystems, showing the importance of government-backed initiatives like Diamond Open Access journals in achieving sustainable systems. Community Engagement and Policy Development: The presentation underscored the continuous involvement of the community with beneficial ecosystems, even post-policy incentives, advocating for policies that support open science and Diamond Open Access journals to ensure long-term sustainability and effectiveness. Infrastructure and Volunteer Support: Tanzil acknowledged the significance of Open Access Journal infrastructure such as OJS developed by PKP, DOI managed by Crossref, and the active role of Relawan Jurnal Indonesia's network of over 700 volunteers in providing technical support and maintaining ethical and procedural standards for journal management.