Best Power Metering Relay for High Power (Water Heater) Application

I have recently fallen in love with the Shelley devices, but they don’t seem to have an energy metering relay that’s stout enough to run my hot water heater, which is 4500 Watts. Is there a similar device with a higher current rating? Wifi is preferred, and I really enjoy local-only operation. MQTT is great, and is how I deal with most of my devices.