If you associate these trackers with person entities:
Then you can simplify your triggers and conditions to:
alias: Thermostat off when gone
description: ""
trigger:
- platform: state
entity_id: zone.home
to: 0
action:
- device_id:
domain: climate
entity_id:
type: set_hvac_mode
hvac_mode: "off"
- device_id:
domain: mobile_app
type: notify
message: Nobody is home, Thermostat is disabled!
mode: single
The state of the zone is the count of the number of people (not trackers) in it. So when it goes to 0 there is no one home and so disables your thermostat.
Also some friendly advice: Why and how to avoid device_ids in automations and scripts