Even though my surface has smooth shading on and is heavily subdivided, the geometry seems to be faceted. Anyone know why?!
if you refer to those segments visible in your first picture then you need to subdivide the other mesh, the ring, the one you use to deform the grid... if you ask about the faces in the third image it is more a smoothing problem, may need an extra subdivision and use a 'set shade smooth' node... but I see you got it covered in the third picture
guess you are using a 2.93 version of blender, that smoothing node may not be there..? I'm new to GN so never used those attribute nodes either