Using small fan and heatsink, temperature is about 50°C when my k3s cluster is idle. I haven't push it that much. The most it goes with not so demanding process is around 65.

in term of power, I didn't connect it to any USB hardware, so a bit diffcult to tell based on my current usage. I have one nvme 2TB and one ax210 WiFi module for the isc-dhcp server, and the other nodes connected to it through lan. Anyway, can use either the 20W adapter provided by orange pi (the white model) or the cheaper version (black) that is available at aliexpress.