Terrain seams

I want to create a game with fully dynamic lighting. I have my directional light set to movable. The problem is that this creates lighting seams on the terrain. You can see the discoloration where the edges of different terrain components meet.

Any way to fix that? The only thing that seems to work is making the light stationary and building static lighting, but I want it movable for a day/night system

As a side question, is there a way to make the terrain polys less obvious? I haven’t done anything special in my material, just a texture with UVs, and setting spec / metallic to 0 and roughness to 1… but I was hoping it could still look smoother than that.

Have thought about smoothing ( averaging ) normals?