Ok from what i understand, this paper is proposing that a very specific substitution of the Copper atom in the place of the lead atom in the lead apatite structure is responsible for this
This only happens at a very specific atomic site but it alters the structure of the material in a way that creates a "Flat Electronic Band" that is key to Supercon
But since it has to be at that very specific site at a very specific atomic proportion it could explain why people are having trouble replicating this material exactly
https://arxiv.org/abs/2307.16892
I think the video the Chinese lab posted is just as ambiguous and unconvincing as the video posted by the original research team.
Ignoring that the video was very blurry and poorly shot, once again they have a sample that only partially levitates over a magnetic field. Not only that, it occasionally switches which side of the flake remains on the magnet. That last bit makes it a bit harder for me to argue that it's a result of impurities and non-uniformity in a superconducting sample.
Personally, I'm not going to be convinced until the actual resistivity of a sample is measured to be zero by several independent labs, and the methodology in doing so is deemed valid by consensus among condensed matter physicists.
The original paper features a temperature to resistivity graph that appears to reach zero below the stated critical point, but the Y-scale is so comically large that the resistivity of plain copper (1.72 x 10^-8 Ωm) would be indistinguishable from zero.