Don't know but bigger is always better for this particular purpose.
The heatsink was larger in the M1 MBPs -- for a chip with less performance.
Like has been said multiple times, the interface block that sits on top of the SoC is not a heatsink and what you say is basically false.
The plate is the hot side of the heatpipe which transfers the heat of the SoC to the radiators, the cold side. Fans blow ambient air across the radiators to transfer heat to the room the machine is in. If someone says heatsink, you should think of the radiator fins or the ambient room. If you look at the Mac Pro CPU cooler or MPX module, you are not calling its interface plate a heatsink. It is the gigantic mass of radiator fins that is the heatsink.
The easiest way to have the SoC run at cooler temperatures is to download a fan control utility and just run it higher RPMs.
If the radiator fins are aluminum, you can go get a radiator fin made of copper, but this is likely impossible as radiator fins are typically welded to the heat pipes, and the fluid inside the heatpipes may even circulate inside the fins. Based on M1 MBP14/16 teardowns, the interface block of the heatpipe, which sits on top of the SoC, is already copper. No point in doing this. The heatpipe systems in today's computers are really efficient at moving heat from one place to another.
It's all in the radiator fins. It's basically wetted surface area, flow rate across that surface area, and the temperature of ambient air. Material heat transfer properties is also big as copper is used in constrained spaces over aluminum. So, bigger radiator fins, more fins (a heatsink with more surface area) would decrease the need for a higher RPM fan. You can trade the other way and have a higher RPM fan driving more air across a smaller heatsink.
For the M2 MBP14/16, just do nothing. It works as designed. People see the chip running a little hotter because the chip has a lot more transistors, runs at a higher clock rate, and is fabbed on a process that didn't bring its power characteristics back to M1 Pro/Max levels. So, it runs a little hotter - the difference is from 30 Watts to 35 Watts, not 30 to 100 Watts - but you get 15% more CPU performance plus 2 more efficiency cores and 30% more GPU performance in trade. The heat is not material as the difference is not noticeable to the vast majority of humans, snd the machine will generally last longer because of the efficiency cores. So it is is nothing but a win.
Mountains out of molehills. And yes, iFixit is actively misinforming you using their snarky language. You shouldn't trust anything they say out of taking things apart and putting them together. It's basically appalling to hear their videos these days when they have "side" commentary on why this or that has changed.
