I have ESR's Qi2 car charger. The top right hand corner of the unit gets really hot. I've measured upwards of 52C. It really needs a heatsink of some sort or a fan otherwise it heavily throttles going from 15W down to 5W. Have you noticed the same with the 3 in 1? I also have Anker's Qi2 Pad. It throttles much less and the temperature stays below 42C. The body appears to be a solid metal heatsink.
I just had a phone, watch and AirPods on the charger and while it does get slightly warm, it’s not hot at all. I think the heat dissipates pretty well for this charger.
