i havent done any work on the materials, i`ve only touched on the light and reflections side.
giving that you are working with imported geometry, displacemnt will be a pain to setup, not to mention that eevee doesnt suport material displacement. if you are serious in archviz and imported scenes from CAD softwares maybe you should invest some money in some addons
https://blendermarket.com/products/bmesh-clean-add-on - for reducing poly and triangulation and also it welds edges together making it easier to subbdivide the planes in blender in order to mesh displace it.
https://blendermarket.com/products/super-texture this one i`ve purchased just for the improvemnt it does to textures giving paralax effect and higher quality control just from the texture it self no other maps required.
But if you want to make this as photorealistic as you can, then you should add envoirment like grass, trees, dirt and grudge maps on materials and grounds, and the most important fact if you are using materials with reflections like wood, metal, varnished materials, plastics you should ad this trick, good guy.