The Xiaomi Mi AIoT Router AX3600 (ipq8071a) uses around 6 watts.
@moeller0 you will find that the idle values are a quite good approximation for the averages even for busy home environments, load spikes happen, but they tend to be brief (there are no real differences between really idle and 'normal' background usage) and drown within idle times. Very active 24/7 p2p usage at high speeds might have a potential to skew the results, but not 'normal' usage (browsing, streaming, downloading, video-conferencing, remote desktop, etc. of an average family).
Edit: my max. values have not been reached while running OpenWrt, but doing a multi-threaded kernel build and multi-threaded ffmpeg/ x264 encoding concurrently (running desktop linux).
Edit2: Number of active ethernet ports and their speed (100BASE-T vs 1000BASE-T/ 2.5GBASE-T, 5GBASE-T, 10GBASE-T) and the intensity of WLAN usage will make more of a dent, than variations of (normal) WAN traffic.