Yes, during installation I was also surprised at the temperature and had taken the trouble to measure it. Without POE consumers, the temperature was around 50°C. The switch has been in operation without interruption since spring, I have no long-term experience (yet). As long as several such Unifi devices are not stacked on top of each other, you can read in the forums that the temperature is unproblematic. Since everything is managed centrally in the Unifi environment, it should also not be a problem to replace a defective switch with a new identical one and have it integrated by the controller.

Yes, the switch gets quite warm, as I have all PoE ports occupied with PoE devices (cams). I would still buy the switch again.

I only have 32°C with 3 x PoE connections. Vertically mounted on the wall. It works :)

Yes, even with only one POE consumer, the switch gets very warm. I have mounted it under a tabletop and am wondering whether I should screw it to the wall to improve the air circulation.