Aggregate of an Aggregate on a chart?

Hi, so I want to make a chart that shows my average hourly electric consumption (I have a few items that have similar data), then end goal would be get something that either exactly computes my electric bill, or gets something useful and close.

I have the data from my solar system, and it’s in lifetime kWh (updated every 5 minutes). I can do difference of lasts/firsts, it gets me my hourly data, and I can do that to get my hourly data for every day. How do I average (or sum, it doesn’t matter) that?

Bonus points if I can split it out so I can get weekend/holiday hours and compare it to weekday hours (since my utility differentiates).

Right now this is what I have, and it shows all the data I want, just not averaged (you can kinda average it with your eyes…but it should be able to do that)

  label: Energy Consumption Billing
  period: 2M
    - component: oh-chart-grid
      config: {}
    - component: oh-category-axis
        gridIndex: 0
        categoryType: day
        weekdayFormat: default
        monthFormat: default
        name: Hour
    - component: oh-value-axis
        gridIndex: 0
        name: kWh
    - component: oh-aggregate-series
        gridIndex: 0
        xAxisIndex: 0
        yAxisIndex: 0
        type: line
        name: Import/Export
        item: solar_system_netkWh
        aggregationFunction: diff_first
        dimension1: hour