How to use the repeat function with button-card to increase brightness?

So Ive recently started using the button-card lovelace card, and I love it.

It has the repeat function on hold. I would like to use it to increase brightness of a light by say % every 500m/s, but I cannot figure out how. I assume I would need something like:

{ "brightness": "states.light.gledopto.attributes.brightness|int + 10" }

But that doesnt seem to work.

My existing yaml is:

cards:
  - aspect_ratio: 11/1
    color: 'rgb(33,150,243)'
    color_type: label-card
    name: Lights
    type: 'custom:button-card'
  - cards:
      - dbltap_action:
          action: call-service
          service: input_boolean.toggle
          service_data:
            entity_id: input_boolean.light_high
        entity: light.jasco_products_unknown_type_4944_id_3235_level
        hold_action:
          action: more-info
        icon: 'mdi:sofa'
        name: Living Room
        size: 27%
        tap_action:
          action: call-service
          service: input_boolean.toggle
          service_data:
            entity_id: input_boolean.light_low
        type: 'custom:button-card'
      - entity: switch.jasco_products_26931_smart_motion_switch_switch
        icon: 'mdi:garage'
        name: Garage
        size: 27%
        type: 'custom:button-card'
      - entity: switch.jasco_products_14291_in_wall_smart_switch_switch_2
        icon: 'mdi:home-account'
        name: Porch
        size: 27%
        type: 'custom:button-card'
    type: horizontal-stack
type: vertical-stack

One solution would be to create a script with the % you want and call it

What would that look like? This part is a bit over my head and I havent been able to find a good example to go off of

How does this look? It isnt doing anything, but im not sure whats wrong

increase_brightness:
  sequence:
  - data:
      brightness: >
              {% set state = (trigger.event.data.action_value|float) -%}
              {%-  if state > 0 -%}
                {%- set state  = states.light.jasco_products_unknown_type_4944_id_3235_level.attributes.brightness + 10 -%}
              {%-  elif state < 0 -%}
                {%- set state  = states.light.jasco_products_unknown_type_4944_id_3235_level.attributes.brightness - 10 -%}
              {%- endif %}
              {{ state }}
      entity_id: light.jasco_products_unknown_type_4944_id_3235_level
    service: light.turn_on
  alias: Increase Brightness