I did a few more tests. Another finding is that the power adapter that comes with the QC Mini is actually pretty decent. I tested the noise level with the original power adapter and my Cioks SOL. No difference. And I'm pretty sure that with the OG QC, which I briefly had a few years ago, there was definitely a difference.
Clearly, Neural have learned from their previous mistakes with the QC and have improved the design of their new hardware accordingly.