With significant advances in Gravitational Wave (GW) observations in the coming years and a new generation of large-scale electromagnetic galaxy surveys reaching maturity, the time is right to bring together experts in these two communities to explore the integration of these datasets for novel cosmological analyses with dark sirens. This workshop aims to develop methodologies for combined data analysis and build a roadmap for advancing the field of cosmology while also utilising GW insights to tackle key challenges in stellar and extragalactic astrophysics.