Unfortunately, at the present time only Samsung smart appliances and a very few other devices can be included in the Energy dashboard. 
As you noted, the Aqara plug is one that works, no one seems quite sure why. Even the SmartThings brand models don’t show up. It’s a mystery. 
You can try asking support. If you get an answer, let us know.
https://support.smartthings.com/hc/en-us
Here is a previous conversation about the topic, FWIW: