Another possibility is downloading from the Noise building datasets (building geometries are needed for calculating sound transmission and reflection), see PDOK - 3D geluid downloads and https://download.pdok.nl/kadaster/3d-geluid/v1_0/2020/gebouwen/2020_NL_3d_geluid_gebouwen.zip (2D + height). Zipped geopackage, data version 2022.04.06