BT not heating to target temp

[SebboGit]

So I just set up BT yesterday evening, I selected Offset Based and AI Time Based and I am well aware the adaption might take some days to fully work. However, I am wondering if it really is this "bad" at the beginning.

7am: external temp_sensor is at 20.2 degree
BT was set to 19 degree during the night, now set to 23 degree, radiator is getting warm

8am: an hour later the external temp_sensor shows 20.6 degree, so it took a full hour to increase the temp by 0.4 degree
BT still set to 23 degree heating

8:30am: the external temp_sensor now has been dropping since 8am and reached 19.9 degree

It is now roughly 10am and the current temp from the external sensor is 20.1 degree

So after 3 hours of "heating" I've lost a total of 0.1 degree and I am still 3 degrees off my target temp.
Radiator is only slightly warm when I would expect the valve to be a lot more open considering we are still way off target temp after 3 hours of heating. This is my 5m² bathroom by the way which did heat up in less than 20 minutes on schedule before I switched to BT.

[SebboGit]

Different room, so different values but:

Bedroom set to 20 degree heating, current temp from external sensor is 18 degree.

Local temperature in Zigbee2MQTT shows 25.1 this is clearly the internal temperature measured by the device, so given these values the valve stays at 0% and the room does not heat up. There is also nothing set as remote temperature here:

But the whole point of switching to BT for me is that I want the TRV to be based on the external temp sensor not the internal one and based on the first picture the current temp is correctly set to my external temp sensor. I don't see this reflected in the Zigbee2MQTT settings for the TRV though.