Right now terrain looks like crap because of constant patterns being visible. This can be easily mitigated by using user painted color map (can be blended to the splats on top) and/or noise map (or any runtime generated worldspace noise). TerrainLit in HDRP looks like something from the 2006 due to this. Please consider improving terrain visual quality. Now that the HDRP layers limited 8 this is especially visible.