Dynamic Beyond 5G and 6G Connectivity: Leveraging NTN and RIS Synergies for Optimized Coverage and Capacity in High-Density Environments. - Valdemar Farré; Juan Estrada; David Vega; Luis Felipe Urquiza-Aguiar; Juan Andrés Vásquez-Peralvo; Symeon Chatzinotas (CoRR, 2025)