It is now easy with the min/max helper to sum-up values (3 phases via Shelly 3EM for example) but this value can’t be used in the energy dashboard.
Yaml customize will fix it but not user firendly. Some other entities can be directly set via the GUI. Please add for these (and other) helpers.
Just noticed this is the reason a Template temperature sensor is not grouped together in statistics with a Min/Max sensor of other temperature sensors. The Min/Max sensor is missing the device_class: temperature
Would be useful to have that!