They are probably using the same Texas Instruments MCU and other components they first implemented in the P3 (they ground the original TI branding off the MCU but it’s well known which component it is)- they basically implemented the original TI application note without change. It was pure sine wave drive then.I read yesterday that the updated ESCs of the P4P-V2 use a sine wave for smoother changes in speed whereas the original P4P ESCs use a square wave. The smoother changes in speed help keep the average sound lower.
This guy mentions more detail about it in his review video starting at about 2:43.
A giant disclaimer is that this is not an area of expertise for me. I am only repeating what I heard and don't know for sure if it's accurate or even makes any sense.
Time will tell what if anything has been changed with the motor drive architecture. Sine wave drive isn’t a new feature for DJI through. The P3 wasn’t square wave, I doubt they took a backward step with the P4 and Pro....