In Sabine's opinion. I've seen Sabine's video when it was posted and intend no disrespect to her. The predominant theoretical explanation for the alleged new superconductor is that it may be a new type of superconductor, not type I or type II, or it may be presenting in unusual ways. There have been a bunch of confusing theoretical prodictions, like anisotropic conduction (how would that affect the way levitation looks)?, chance-based copper substitution in the lattice that could lead to superconducting clusters in what is otherwise just normal lead apatite (how would that affect the way levitation looks in a bulk chunk like that?), etc.
Plenty of people who know the theory of superconductors are sceptical. They're not wrong about the theory. It's also worth pointing out that every previous time a new superconductor critical temp limit was broken in a major way, superconductor theory saying it shouldn't be possible was a cause for early scepticism amongst those who knew the theory. Sabine's gut reactions in a YouTube video doesn't make the result very unlikely. It doesn't make her wrong either, she's right that all existing superconductors, if pure and homogeneous, would not behave like that on a magnet. It is also the case that all existing superconductors do not superconduct at room temperature and ambient pressure. It is also the case that (absent fraud, which is on everyone's mind after Ranga Dias) we don't know of any material that could plausible behave the way that video shows something behaving. The only thing I can think of that could behave that way would be impure/heterogeneous diamagnetic material, but like 15x as diamagnetic as the next highest non-superconductor, which means if that material exists we don't know about it. If it was fraud, it would be with a magnetised sample on a magnet like that. The reason I think fraud is the only option if it was a magnetised sample is because that's a really, really obvious explanation for the effect and they have to have measured the sample for magnetism before putting it on a magnet. They would also literally feel it/see it/hear it while placing the sample on the magnet. Also it would almost certainly have to be composed of different elements than they describe, because lead apatite with copper definitely should not be ferromagnetic at all.