Template sensor - trigger.from_state syntax?

Configuration
1

I cant get this to work. The states not there when rendering is logical. But it doesn’t work after some time when state changes. Where do I go wrong with my icon-logic?

- sensor:
    - name: "Yahoofinance MMRI"
      unique_id: yahoofinance_mmri
      state: >
        {% set US10YR = states('sensor.yahoofinance_tnx') | float %}
        {% set DXY    = states('sensor.yahoofinance_nyicdx') | float %}
        {{ ((DXY * US10YR)/1.61) | round(1, default=0) }}
      attributes:
        icon: >
          {% if trigger.from_state.state < trigger.to_state.state %}
             mdi:trending-up 
          {% elif trigger.from_state.state > trigger.to_state.state %}
             mdi:trending-down 
           {% else %}
             mdi:trending-neutral
          {% endif %}

Log:

2023-12-17 22:05:19.236 ERROR (MainThread) [homeassistant.helpers.template] Template variable error: 'trigger' is undefined when rendering '{% if trigger.from_state.state < trigger.to_state.state %}
icon: mdi:trending-up
{% elif trigger.from_state.state > trigger.to_state.state %}
icon: mdi:trending-down
{% else %}
icon: mdi:trending-neutral
{% endif %}'
2023-12-17 22:05:19.237 ERROR (MainThread) [homeassistant.helpers.event] Error while processing template: Template<template=({% if trigger.from_state.state < trigger.to_state.state %}
icon: mdi:trending-up
{% elif trigger.from_state.state > trigger.to_state.state %}
icon: mdi:trending-down
{% else %}
icon: mdi:trending-neutral
{% endif %}) renders=2>
Traceback (most recent call last):
File "/usr/src/homeassistant/homeassistant/helpers/template.py", line 569, in async_render
render_result = _render_with_context(self.template, compiled, **kwargs)
2

You can’t use the trigger variable if there isn’t a trigger… also, if your goal is to have the template change the actual icon of the entity, you shouldn’t be defining icon as an attribute.