What do you think that would show?
As I see it the heat dissipation is caused by the combination of 18W power usage from the GPU in combination with CPU load.
The 18W seems to be caused by the GPU requiring maximum memory clock to drive multiple displays for some configurations. This looks to me more like a limitation of the RDNA architecture in the AMD GPU. Linux should make no difference, or?
You could potentially tweak the fan curves to allow the MBP to run hotter but with lower fan rpm, but I am not sure that would lead to a better solution.