@sarahlenker Don’t worry about the miss. Let me say you’re really gentle and I really appreaciate your answers. They’re helpfull! 
About the texture samples and draw calls I missunderstood, now is clear. Anyway, I’m already working with hierchical instanced static mesh and few master materials to instance dynamically via bp. I already streaming textures and also I already set max streaming poolsize changing value in the config folder directly. (I tried with 4000). I’m already working to optimizing uv scale based on dimension of mesh in the scene and their importance, trying also to have all uvs in the same udim. Now I’m realizing a texture atlas with 1k normals map and 512 roughs for my rooms, the rooms being the largest assets in the scene I wanted to texture them at 2k to be safe, but I decided to try with 1k not knowing in more detail the impact of textures on non-high-end PCs. Probably the only thing I’m missing is to merge all material slots in one. About this topic actually I really don’t know how to iterate on each slot after merge them. About lightning, I’m using Lumen, because I want a bit of reflections and to avoid baked lights not reacting to players and moving stuffs like AI/Objs. I’m working with stationary lights and I’m trying to reduce the numbers of total lights using emissive textures also.
What do you think about it, Am I doing well? Let me know!