Repeate phone notification

Configuration
4

OK, I can understand that.
I assume you would want some kind of time delay between the 3 notifications?

Personally I would switch from a device trigger to a state trigger, then have 3 triggers.

  triggers:
    trigger: state
    entity_id: domain.WhatEverItIs
    to: "on"

    trigger: state
    entity_id: domain.WhatEverItIs
    to: "on"
    for:
      minutes: 2

    trigger: state
    entity_id: domain.WhatEverItIs
    to: "on"
    for:
      minutes: 10