Questions about Trend integration

I have a few questions about the Trend integration.
I understood it like this:
min_gradient=temperature difference/(minutes x 60)
So if I want a temperature difference of 0.01 °C to trigger within 6 minutes, that would be 0.01/3600=0.000027778

My configuration.yaml says the following:

template:
   - sensor:
     - Name: Attic 1 Temperature Trend
       state: >
           {% if is_state('attic_1_temp_rising','on') %}
           rising
           {% elif is_state('attic_1_temp_falling','on') %}
           falling
           {% else %}
           steady
           {% endif %}
       icon: >
           {% if is_state('attic_1_temp_rising','on') %}
            mdi:thermometer-chevron-up
           {% elif is_state('attic_1_temp_falling','on') %}
            mdi:thermometer-chevron-down
           {% else %}
            mdi:thermometer-minus
           {% endif %}
          
binary_sensor:
   - platform: trend
     sensors:
       attic_1_temp_falling:
         friendly_name: "Attic Thermometer 1 Trend"
         entity_id: sensor.attic_thermometer_1_temperature
         sample_duration: 360
         max_samples: 10
         min_samples: 2
         min_gradient: -0.000027778
         device_class: cold

       attic_1_temp_rising:
         friendly_name: "Attic Thermometer 1 Trend"
         entity_id: sensor.attic_thermometer_1_temperature
         sample_duration: 360
         max_samples: 10
         min_samples: 2
         min_gradient: 0.000027778
         device_class: heat

Nevertheless, it always remains steady.
As you can see, the temperature rises continuously.
Temperature

Maybe the Trend integration is not suitable for my project.
For example, I don’t know how often my sensor updates.
I have 4 identical sensors and as you can see the update rate is different.

Unfortunately, I haven’t yet figured out how to log the interval so that I can see how often Temperature “last_updated” really occurs.

What I actually want is that after 2 consecutive temperature increases there is “rising” and after 2 consecutive temperature decreases there is “falling”.
I actually don’t care about the time period.

Nevertheless, I would like to understand how exactly the trend sensor behaves in detail if you only use short measuring spans (in the minute range)

Thank you!