Template Sensor that changes for each new attribute item

Configuration
1

I have this rest sensor here:

  - platform: rest
    name: ToDoist Activities Completed
    resource: https://api.todoist.com/sync/v8/activity/get?page=0&event_type=completed
    value_template: '{{ value_json.count }}'
    method: POST
    json_attributes:
       - events
    headers:
     Authorization: Bearer MYTOKEN

It lists all completed Tasks from my ToDoist List in the actual week. The attributes gives all completed Tasks in a list, so this here

{% for x in states.sensor.todoist_activities_completed.attributes.events %}
  {{ loop.index }}. {{ x.extra_data.content }}
{% endfor %}

would give back

  1. Cleaning kitchen
  2. Home Assistant
  3. Shopping

for example. I want to create a new template sensor that changes the state every time a new item was added. The thing is if I would add another three items in a shorter time then the scan interval of the rest sensor, the state would change to the third, last added item, but I want to have a sensor that “sees” that three new items where added, and for each new item, the state changes - Is that possible?