I think many people would disagree that Unreal Engine can’t produce photo realistic renders. So, the question is somehow the wrong way around. There are lots of apps, like Blender, 3ds max, Twin Motion, Revit, etc. which allow data import into Unreal.
But to answer your question: You can export Unreal Engine meshes to FBX or OBJ and you can export textures as well. But this is a bit limited. As far as I know there is no other app that can use unreal scenes to create “better” renders. You can do post processing inside unreal with PPV volumes.