Or "when the only occupant opens the front door and drops off the network, turn off all lights, arm the alarm, turn off the stereo, and yell at me if the cooktop is drawing power".
I'm a zigbee fan, mostly because there's such a wide variety of devices.
I almost exlusively use zigbee2mqtt [0] reference to find devices that suit me. Searching for `meter` gives a lot of options, you'd have to do more investigation to find something that supported 40A, but my guess would be that a clamp meter is likely your best option.
It's also possible that you could use one of the DIN rail options in your fusebox, but I haven't looked at the current ratings.
For standard power outlets I have "smart plugs" that measure the power draw, are there ones that support 40A/240V appliances?