Im assuming a hub with gearing, despite having less room for actual motor, generally runs cooler given the same load than without a gear.
Runs cooler but can dissipate 1/3rd of the heat of a DD.
There’s no hub motor with strong steel quiet internal gears available?
Never heard of such a thing, in order to be quiet, steel gears would have to be in some kind of lubricant bath. I've never seen such a thing for sale in my history here.
Maybe with the planetary gear heat transfer is further obstructed?
I dunno, i imagine the gear carrier helps collect some of the heat. That's about all it does.