ApexChart - How to show AVG of the MAX over time period

Configuration
1

Using ApexChart (sorry if wrong forum).
I have it setup, but I dont know how to add an AVG.

I want to take the Max temperature over 14 days, and average that.

Not sure how to do that though.
Here is what I have so far:

image
image984×482 34.8 KB 

type: custom:apexcharts-card
graph_span: 14d
yaxis:
  - id: Max
    min: 0
    max: 105
  - id: Min
    opposite: true
    min: 0
    max: 105
  - id: Avg
    opposite: true
    min: 0
    max: 105
    show: false
span:
  end: day
header:
  show: true
  title: Pool Temperature 30 Days Max/Min
  show_states: true
  colorize_states: true
series:
  - entity: sensor.pool_temp
    name: Today Max
    yaxis_id: Max
    type: column
    group_by:
      func: max
      duration: 1d
    color: rgb(255, 0, 0)
    data_generator: ''
  - entity: sensor.pool_temp
    name: Today Min
    yaxis_id: Min
    type: column
    group_by:
      func: min
      duration: 1d
    data_generator: ''
  - entity: sensor.pool_temp
    name: Average Max
    yaxis_id: Avg
    type: column
    color: rgb(255,165,0)
    group_by:
      func: median
      duration: 14d
    data_generator: ''
    show:
      in_chart: false
2

I am looking for the same thing.
I want to display my average energy cost per day per entity in the header. But it always takes the current value.
I tried it with hidden entities that average every day. But how can I tell the header value to be an average over all?

Best,
Denny