Question about EQ-3 Radiator thermostat

I can confirm the answer from 'Belliger91'. It absolutely needs the AP - it is the heart that connects all the end devices, such as the thermostat etc.. It also needs a functioning WLAN and cannot be controlled via Bluetooth.
As 'Belliger91' has stated, the system can no longer be controlled via the app if the connection from the AP to the WLAN is interrupted. So far I have never experienced this (1 year in use) - but I have a lot of respect for it.

Homematic has a central box that aggregates all data. It is therefore not possible to access individual components directly.

The IP in the name means that the whole thing works via the cloud. This is of course convenient and simple, but has the disadvantage that if it is not accessible, you can no longer control your Smarthome system via the app.

Homematic has a central box that aggregates all data. It is therefore not possible