It's an interesting thought experiment. I can entertain the idea of a superconductor staying a secret in a military environment, but I can't imagine it getting widescale commercial use and staying a secret.
https://en.wikipedia.org/wiki/Brainstorm_(1983_film)
a researcher builds a device that can record and play back experiences which takes up most of a room, in a meeting with his boss, he receives some secret microchips made of a room temperature superconductor that he uses to make headsets.
My understanding is that a major hurdle is just how tiny everything is on modern chiplets. If I remember right....someone managed to reverse engineer the Intel 8086 or the 8080....but my understanding is that our lithography is so complex at this point you can't accurately reverse engineer the physical chip layout. If one could reverse engineer the physical layout and chemical layers...you could probably use that information to reverse engineer the photolithography mask and chemical etching step.
TLDR: we can't reverse those modern server CPU's ....we can only learn via what the fan or the chiplet owner be it Intel or and or apple decides to release regarding architecture or chip layout.
You'd need to use gamma spectrography to map out more modern chips. I'm sure someone's got the equipment somewhere; the chip manufacturers themselves must verify they got a good etch somehow.