Dont know about current ones, but the GP4 i think was also plagued by heat issues as i recall.
Sure metal can conduct heat, it cam also trap heat, if you want it conducted the best thing are to have the heat generator touching the metal to facilitate transfer of heat as optimal as possible.
But that just bring you half way there, the metal in turn have to offload that heat to something, in most cases air, and to do that optimal you will need a steady flow of air over the metal, and to further increase heat transfer you need as much surface area as possible.
This is why you see computer CPU coolers have a lot of fins to increase its surface area by a large factor, the pickup point from CPU to the cooler can be small but exchanging from heat in the metal of the cooler to air you need a larger surface area as its a less optimal to transfer heat into air.
This is why water cooled computers are a step up from air cooled, its the same rules in play but transferring heat into water are more easy, but you still need a radiator to transfer the heat of the water into air.
Again here whit water cooling you can go passive, but its way less effective so you will see much higher temperatures.
In general i find that with computers and say comparing a 2 fan ( 120 mm ) heat pipe cooler to a water cooled setup with a dual fan ( 120 mm ) on the radiator, you can in general get off with running the fans on the radiator at half the speed the fans need on a air cooler to get the same temperatures, and amping things up with overclocking the CPU mean the water cooled rig can go further up in CPU speed.
Off course you can go passive cooling on a computer CPU too, but you at least need a heat pipe cooler then, to use liquid / gas in the heat pipe to aid in heat transfer, and then you probably have to use a CPU that dont generate as much heat.
To my knowledge no action or dash cameras have the main heat generator ( the SOC ) directly in contact with the chassis, this might even be a bad idea as you will have a direct heat path so at least some point of the chassis could become almighty hot.
