Return sensor list and them format it

Configuration
1

I am trying to integrate a sensor that I created that outputs data based on input_boolean status. This is an integration for a play button of a robot vacuum cleanner. The idea is when I dont have any rooms selected or all of them on the play button custom field appears “Clean the entire house”, if I select individual rooms they will appear, if selected, on the play button, letting me know which rooms it will clean. So far I managed to create the sensor, and it outputs the values in the right way, “Clean the entire house” if all selected or none, and it will create a list of the input_booleans that are on.

The code
Sensor (sensor.vacuum_what_is_cleaning):

{% set all_rooms = {
   'bedroom': 'Bedroom',
   'toilet': 'Toilet',
   'hallway': 'Hallway',
   'bathroom': 'Bathroom',
   'living_room': 'Living room',
   'kitchen': 'Kitchen'
} %}

{% set ns = namespace(rooms_on=[], rooms_off=[]) %}
{% for k, v in all_rooms.items() %}
    {% set ib = 'input_boolean.vacuum_room_cleaning_' ~ k %}
    {% if is_state(ib, 'on') %}
        {% set ns.rooms_on = ns.rooms_on + [v] %}
    {% elif is_state(ib, 'off') %}
        {% set ns.rooms_off = ns.rooms_off + [v] %}
    {% endif %}
{% endfor %}

{% if ns.rooms_on | count == 0 or ns.rooms_off | count == 0 %}
    Clean the entire house
{% else %}
    {{ ns.rooms_on }}
{% endif %}

Custom field on a custom:button-card

custom_fields:
  rooms: '[[[ return states["sensor.vacuum_what_is_cleaning"].state; ]]]'

My problem now is how do I integrate this into a button label and format it so it doesnt simple appear as [‘Item1’, ‘Item2’, …]