Re PS: What’s gonna convince you?
This is extremely ordinary 'evidence'
Claims don't require special evidence whether they are extraordinary or not. "Extraordinary" claims can be proved with the same kind of evidence as other kinds of claims. Relativity was first tested by taking pictures of an eclipse, pretty pedestrian evidence relative to the cosmic scale of it's implications.
What is true is that, the higher the confidence of your prior belief, the less impact new evidence will have. So extraordinary claims simply require more evidence, because our prior is that they aren't true with fairly high confidence.
It's just standard Bayesian reasoning (apologies if I'm misusing the terminology).
Given how much prior research has been done on superconductors, how attractive a target they are for research, and the demonstrated history of fraud in the field - it's not unnatural to retain skepticism concerning this story.
Doesn't mean the story is fraudulent or falsely believed to be fraudulent; it simply means that more evidence is needed to settle this convincingly. I'm sure will get that soon enough - either way.