Custom-ui to modified the icon associated to a binary_sensor

So I have over 70 smart entities in my house and the only way to make everything evidently accessible, is through a picture-elements cards, which have very limited icon customization, therefore I’m using custom-ui to have a more complete view of the states of the entities that are showed. For example, this is the custom-ui for my dishwasher.

sensor.dishwasher:
  templates:
    icon: >
      return 'mdi:dishwasher';
    icon_color: >
      if (attributes.process_state === 'Washibg') return 'rgb(255,114,92)';
      if (attributes.process_state === 'Rinsing') return 'rgb(164,99,242)';
      if (attributes.process_state === 'Dry') return 'rgb(255,138,183)';
      if (attributes.process_state === 'Night Dry') return 'rgb(108,197,176)';
      if (attributes.process_state === 'Standby') return 'rgb(244,189,94)';
      return 'rgb(66, 105, 208)';
    friendly_name: >
      return attributes.process_state + " - " + attributes.remain_time + " left"

Now I’m trying to do something similar to a Hue motion sensor. I want it to show the movement/no movement icon and to have different colors depending if there is motion, no motion and if the illuminance is below a certain threshold (a light turns on if it’s dark enough when motion is detected). This is what I have and it doesn’t work:

binary_sensor.hue_motion_sensor_cave_motion:
    icon: >
      if (state == 'on') return 'mdi:motion-sensor';
      return 'mdi:motion-sensor-off';
    icon_color: >
      if (state == 'unavailable') return 'rgb(193,193,193)';
      if (state == 'on') return 'rgb(251,210,41)';
      var illuminance = entities['sensor.hue_motion_sensor_cave_illuminance'];
      if (illuminance && illuminance.state > 8) return 'rgb(0,255,0)';
      return 'rgb(66, 105, 208)';

In this version of the template, the icon doesn’t even appear (although clicking its location shows its card). If I don’t template the icon itself (just the color), the color choice are ignored and the default colors are used (which I confirmed by using unrelated colors, which never showed up).

So how can I make this work, if possible? Thanks.

No need to use custom ui.
Both icon and icon color can be dynamically changed by cardmod.
Google “picture elements small tutorial” - 1st post - how to style dynamically.

Oh, I wasn’t aware that card-mod could apply within a picture-elements card. I thought it was its own card. Thanks, I’ll look into it.