I have integrated notifications from Home Assistant to Android TV with the help of the Notifications for Android TV app. Works flawless and even supports images and icons.
Have made an automation that pauses the TV and shows an image from the doorbell camera.
Small improvements in the everyday life 🙂

Notification TV:

History in Notification for Android TV app:

Automation:

# Doorbell notification pushover and tv
- alias: Doorbell notification_pushover_tv
  id: doorbell_notification_pushover_tv
  trigger:
  - platform: state
    entity_id: sensor.doorbell_action
    to: hold
  - platform: state
    entity_id: sensor.doorbell_action
    to: release
  condition: []
  action:
  - choose:
# Tv off
    - conditions:
      - condition: and
        conditions:
          - condition: state
            entity_id: remote.living_room_hub
            state: 'off'
      sequence:
      - service: timer.cancel
        entity_id: timer.doorbell
      - service: timer.start
        entity_id: timer.doorbell
      - service: camera.snapshot
        data:
          entity_id: camera.main_door_cam_stream
          filename: '/config/www/snapshots/main_door_camera_snapshot.jpg'
      - service_template: notify.pushover
        data_template:
          title: "Doorbell rang!"
          message: "Visitors at the main door!"
          data:
            attachment: /config/www/snapshots/main_door_camera_snapshot.jpg
            html: "1"
            sound: "bike"
# User home and tv on
    - conditions:
      - condition: and
        conditions:
          - condition: state
            entity_id: group.all_people
            state: 'home'
          - condition: state
            entity_id: remote.living_room_hub
            state: 'on'
      sequence:
      - service: timer.cancel
        entity_id: timer.doorbell
      - service: timer.start
        entity_id: timer.doorbell
      - service: camera.snapshot
        data:
          entity_id: camera.main_door_cam_stream
          filename: '/config/www/snapshots/main_door_camera_snapshot.jpg'
      - service: notify.living_room_media_center
        data_template:
          title: "Doorbell rang!"
          message: "Visitors at the main door!"
          data: 
            duration: 15
            font-size: max
            transparency: 50%
            position: bottom-right
            image:
              path: "/config/www/snapshots/main_door_camera_snapshot.jpg"
      - service_template: notify.pushover
        data_template:
          title: "Doorbell rang!"
          message: "Visitors at the main door!"
          data:
            attachment: /config/www/snapshots/main_door_camera_snapshot.jpg
            html: "1"
            sound: "bike"