NeWifi3 D2 power consuption and routing performance

can anybody tell me his experience with the power consumption and routing performance of the NeWifi3 D2 router with openWRT?
I do not need Wifi but I would like to use the router at a glass fibre connection with 300 Mbps and more in the future. Is the router capable to route with full speed IPv4 and IPv6 from WAN to LAN?
What about the power consumption in idle mode with Wifi switched on and off?

I am a bit lazy to unplug mine and attack a wattage meter to it. With the pre-installed thermalpad between the SoC and the metal top cover, I never feel warm when I touch it - always dead cold.

Anyway, I am having serious issue with my Newifi D2. It randomly hangs once a day. Sometimes only the router function hangs with its VLAN switch still works. Other times the device hangs completely and needs a hard reboot. I am not really sure it is a hardware related problem or it is OpenWrt compatibility. Tried both 18.06.5 and 19.07.

I'll buy another one from China and try my luck again. At $17.5, no other model can beat its hardware. In the meantime, I'll live with it while studying how to use OpenWrt and set up various services.