Just by clicking on Arxiv I see lists of people with similar names, but if you look specifically for them they are only on this paper and the sibling paper with the levitation: Sukbae, Kim and Young-Wan. Kim is also on the other paper without the dash in his name.

Searching in scholar, researchgate, web of science, I cannot find anything.

I have checked out the levitation video, but I see no levitation there, just a magnetized thing with low mass. The typical Meissner effect levitation is done by cooling from above Tc, while keeping your superconductor separated from the magnet a small distance. The flux lines get pinned once you cool down below Tc and you can remove your spacer leaving your SC levitating. This is not that.

In any case, I fully agree with your last sentence: The fabrication procedure is simple enough that anyone that wants to replicate it, can do so. I really would love to be proven wrong, ambient SC would be an absolute civilization changer, but I don’t think this is anything of the sort.