I agree with you that voltage shifting is probably the best way to handle it.
That said, in my case the problem went beyond what was practical. I actually got macOS running, but the real issue was thermal behavior. The heat pipe runs from the fan toward the CPU, and there is a small exposed section of the motherboard in that area. Right underneath sits the temperature sensor.
That sensor seems to get affected so heavily that the system constantly reports overheating to the motherboard microcontrollers, which then immediately throttles the device hard. So yes, it works, but only to the point where using it stops being enjoyable.
On Windows, the same hardware performs much better because the thermal response kicks in around 10 to 12°C later. If that same behavior could be achieved under macOS, the device would actually run very well.
I tested this on three different mainboards and saw the exact same issue on all of them, so at least in my case it was not just a one-off board defect. I also tried a hardware fix for the sensor, but once the case was closed, the problem came back. I looked into solving it in software as well, but without access to the board’s microcontroller, that was basically a dead end. Disabling the sensor entirely would have been another option, but that was simply too risky.
So in the end, I put the project aside. It is not that macOS itself was the problem. The main issue was a temperature sensor that reacts too quickly or too aggressively. If someone finds a reliable way to handle that under macOS, the project has real potential. In my case, though, it just was not worth pushing further.