I baked high poly meshes' details into low poly meshes and textured them in Adobe Substance Painter. When I import the textures back to Blender, it looks different. It seems that the problem comes from the metallic map. How do I fix this?
Edit: I took a second look at your normal map texture which was disconnected in your file and it seems that your bake has gone wrong. We can see the ugly geometry around the key's hole. I don't think that's how it was supposed to look.
Aside from that, ticking [x] Auto Smooth still stands.