Change uptime to timestamp

[genestealer]

Can I suggest changing uptime, to a last boot timestamp. That way Home Assistant will automatically set the time formatting. Like this:

Mqtt auto discovery parameters :

{
  "name": "Last Boot",
  "state_topic": "xxxx",
  "device_class": "timestamp",
  "value_template": "{{ as_datetime(value) }}",
  "unique_id": "xxxx",
   etc,
   etc
  }
}