Normal Map have hard seems- Is there any way to fix it?

I'll suggest to use multi map exporter in zbrush, setting normal map to tangent, smoothuv, sNormals and FlipG i think zbrush by default use opengl type of reading G channel, so it's inverted by default if you are planning to work on a directx based substance project, simmilar errors happened to me in maya, so i had to flip g &/or r channel to make the seams smooth in viewport, by the way those hard seams starts to dissapear when applying all the textures you need.