Thanks for the report. NormalMaps should already have an effect in ViewportFrames (I think I see it subtly in your video?), but metal objects look very different. This is because ViewportFrames don’t have the full set of lighting features the 3D view does - mainly they don’t reflect an environment map. They only reflect a uniform ambient color for the environment, which makes metals look like plastic.
We have some ideas to improve this, but VF improvements are currently on the backlog in favor of other projects.