I use the modeling tools in unreal engine to subdivide and displace meshes because that way, the file size is kept very low. Import the mesh as low poly, convert to nanite, use modeling tools to subdivide and displace.
But we need to be able to use tiling textures to save time and make things easier so a distance based nanite might help so you can use very large static meshes. I have a feeling this won’t be possible so we will have to painstakingly build very large static meshes/terrain using smaller meshes.