Automation help for Solar overprduction usage for heating rod

Configuration
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1

I would need some advice on how to configure an automation to feed a 3kW heating rod with 3phases (1kW) each connected to a Shelly Pro 1PM Switch when solar overproduction occurs and shouldn’t be sold/feeded into the grid.

I want Shelly1 enabled when 1kW+ occurs, second Shelly enabled when another 1kW (so 2kW in total) occurs and the third Shelly when another 1kW (so 3kW in total) occurs.

I am bit struggling with this kind of setup as 1st Shelly is obvious but 2nd and 3rd I can’t figure out on how to deal with it.

Also of course all Shellys should be disabled when no more solar overproduction occurs and the sensor reports less than 100W overproduction.

Any recommendations or workflow on how to get this done?

Here is one example I started off but the 2nd Shelly is of course enabled when 2000kW+ (so 3000kW+ in total) is reported which doesn’t make sense.
I have disabled the turning off sequence as of now but struggle a bit with the full setup:

alias: Heizstabsteuerung bei PV Überschuss
description: von 1100W bis 3100W in 3 Stufen schaltbar
trigger:
  - platform: numeric_state
    entity_id:
      - sensor.strom_zuruck_ins_netz
    id: PV Überschuss - unter 100W
    below: 100
  - platform: numeric_state
    entity_id:
      - sensor.strom_zuruck_ins_netz
    above: 1100
    below: 2100
    id: PV Überschuss - 1100W bis 2100W
  - platform: numeric_state
    entity_id:
      - sensor.export_power
    above: 2100
    below: 3100
    id: PV Überschuss - 2100W bis 3100W
  - platform: numeric_state
    entity_id:
      - sensor.strom_zuruck_ins_netz
    above: 3100
    id: PV Überschuss - über 3100W
condition: []
action:
  - choose:
      - conditions:
          - condition: trigger
            id:
              - PV Überschuss - unter 100W
        sequence:
          - service: switch.turn_off
            data: {}
            target:
              entity_id:
                - switch.heizstab_1
                - switch.heizstab_2
                - switch.heizstab_3
        alias: Stäbe 1,2 und 3 AUS (unter 10W)
      - conditions:
          - condition: trigger
            id:
              - PV Überschuss - 1100W bis 2100W
        sequence:
          - service: switch.turn_on
            data: {}
            target:
              entity_id: switch.heizstab_1
            enabled: true
          - service: switch.turn_off
            data: {}
            target:
              entity_id:
                - switch.heizstab_2
                - switch.heizstab_3
            enabled: false
        alias: Stab 1 AN / Stäbe 2 und 3 AUS (1100W)
      - conditions:
          - condition: trigger
            id:
              - PV Überschuss - 2100W bis 3100W
        sequence:
          - service: switch.turn_on
            data: {}
            target:
              entity_id:
                - switch.heizstab_1
                - switch.heizstab_2
          - service: switch.turn_off
            data: {}
            target:
              entity_id: switch.heizstab_3
            enabled: false
        alias: Stäbe 1 und 2 AN / Stab 3 AUS (2100W)
      - conditions:
          - condition: trigger
            id:
              - PV Überschuss - über 3100W
        sequence:
          - service: switch.turn_on
            data: {}
            target:
              entity_id:
                - switch.heizstab_1
                - switch.heizstab_2
                - switch.heizstab_3
        alias: Stäbe 1,2 und 3 AN (3100W)
mode: restart
trace:
  stored_traces: 10000