Designing terrain heights, with the actual texture displacements?

I have a library of mega scans textures, with some great 2k cliff-rock displacement & or height maps,
does anyone use them for designing Terrains themselves?

Rock to rock, Cliff to Cliff.

So the the Terrains height displacement matches the shaders displacement close/far view?

I have Unity tools that take in Heights for the shader, Normals for the terrain, but not blending displacement & Terrain heights...for a final detailed height map based on splat channels for your terrain.

that is the dis-connect.