Issue occurs with Corona ONLY BECAUSE it is poorly optimised for Mac silicone! Simple as that!
I dont work for Corona but didn't you see the graphs and comments in this thread?
The take home points I see is - just because a native render engine 'claims to be using 100%' of the CPU doesn't mean it is. Is there any proof? Can you show how the native render engine is utilizing the CPU to its fullest? Are you sure the native render engine isn't reducing consumption so those % numbers are higher while reducing the actual performance of the CPU to ensure the CPU doesn't throttle?
I see results from the Ultra Studio in another thread which show no reduction due to higher thermal regulation, so if the Mac laptop is experiencing this isn't this a direct enough comparison to throttling? What are you trying to achieve, as TomG has noted if you down throttle the CPU its the same as using low power mode correct?
Here is an example:
I use a 3080RTX GPU in a laptop, I understand due to power/thermal limitations that my 3080 is about half the performance of a desktop 3080. In this situation my preference to be mobile is the limiting factor, not my expectation that it should match the desktop performance of a 3080.
Example 2:
Imagine you have 2 identical computers, First computer is at room temperature and when it hits 90degrees centigrade it throttles to keep the components cool, thus you have the first computer reducing CPU power even though it stays at 100% the entire time = slower render time.
Second computer is kept in room temperature of -20 degrees. No matter how hard you push that CPU its going to stay at 100% the entire time and not throttle because it doesn't ever reach 90 degrees centigrade. Second computer is going to finish the render faster.
This is oversimplified due to how you cool your CPU etc however I think the point is clear.
Also you can check on youtube for yourself search "mac pro throttle" and filter by the last year, you will see plenty of videos with similar issues regardless of 3D.