I've done experiments with heatpipes to get heat from speaker units to a heatsink on the external back of the cabinet. This was to reduce thermal compression from Cu coils heating up. Only worthwhile on the midrange unit of a big 3 way speaker. It would be very useful in a small 2 way but the cost would then be crazy.
The pipe went up the pole and stuck into the external heatsink. The bottleneck was pipe to heatsink. There was hardly any difference between the pole (inside the coil) and the end of the heatpipe.
Maybe a bit overkill but you might be able to get a sample heat pipe if they thought you would buy 100s
An important point to note is that the success of "chip to ambient" is actually measured by how hot the
external heatsink gets with a given power dissipation. Caveats about comparisons with similar heatsink size bla bla .. it means the heatsink is closer to the chip temperature. It's the temp difference between heatsink & ambient that drives how much heat it is taking from the chip (and into the air).
If the heatsink is cool, not much heat is coming that way and the chip will be hotter to drive heat through less efficient paths.
You can play games like handing someone a heatpipe to stir his hot tea or coffee
