Raytracing and Lumen have been working since preview 2.He is not too, he is simply walking around on an already made scene.
And like pointed out below:
Ray tracing, Lumen, and Nanite are not supported on Mac. The reflections in this scene are standard probs and planar reflections.
I think we can safely discard both has not UE dev but people wanting to make content.....
Nanite is going to be a while as Metal currently has a limit of 500,000 resources per argument buffer and nanite needs at least 1 million.
That resource buffer limitation is one of the reasons there are so few DX12 ports to Mac currently.
Apple is aware that that limit is a huge thorn in our collective sides and they say they are tackling the issue but don’t have a current ETA.