As much as I agree with you on the merits of zigbee over flashing alternate firmware to wifi devices, you may still be better off using the wifi plug if you want accurate power monitoring. It seems the zigbee power monitoring smart plugs have a sampling time issue. Have a read of this topic:
https://community.home-assistant.io/t/zigbee-smart-plug-with-power-monitoring/263162
FYI: the Brilliant plugs are still tuya-convertable.