yes,Nope. It is not. If removing the heat from the chips becomes easy, the limitation becomes the overall heat rejection by the system. So the systems which are already limited by it, such as the F-35, would not benefit much. The space is different. Most things aren't cooled well in the space. There is no weight or cost margin for big heat exchangers. Hence the chip itself being more conductive would still make a significant difference.
people can think of it this way. In Data centers, the GPUs need various cooling methodology to transfer heat off it first but then will still need liquid to circulate through other areas until it cools down. As such, that's imo why cooling is a much larger issue on something like F-35 than Burke. The former has two main constraints and the latter only has to worry about the radar system itself overheating.