EmonLib VS esphome-energy6channel

I also use the Open Energy Monitor project. https://openenergymonitor.org/

I knew https://openenergymonitor.org/ a year ago. Maybe It is your interest

You may take a look at https://openenergymonitor.org.

https://openenergymonitor.org/ would be a good place to start, it's a mature project where the hard work is done.

You'll probably find the resources available on the OpenEnergyMonitor website quite useful, specifically their documentation on electricity monitoring. That covers theory, how to perform the required maths on an Arduino, and how to select the correct sensors etc.

Here's the one I use, good combination of hackable and user friendly, although it took a bit of research to understand what kit and add-ons I needed cause it's got a good number of possible confegurations: https://openenergymonitor.org/

I use Open Energy Monitor gear at home to monitor my (wholesale) power price and solar generation. They have off-the-shelf gear for EV chargers where the feed wattage is controlled. All you would need is a billing aspect.

You can also look at https://openenergymonitor.org/ . The unit that goes in the electrical box is ESP8266-based, so if you don't want to use their software you might be able to get it running in esphome.

Lots of ways. Sense.io. a few open source ones, iotawatt.com. Haven’t looked at this one too much https://openenergymonitor.org