The team also shared a collection of tips, tricks, and best practices for the new scenes. You can install Terrain Tools with additional Terrain painting brushes and utility tools to help you with worldbuilding.
New demo scenes have 50 million triangles rendered in a few view angles and contain a variety of custom trees from SpeedTree.
Unity 2021.2's HDRP also allows you to create realistic and dynamic skies with the new Volumetric Clouds system. The TerrainData assets can then be shared between HDRP and URP projects.