Best comprehensive SmartHome program

But something else... @TaiiTvv isn't by any chance related to @Taitv789 (and some others)? ;)

No idea if he is Taitv789, but with the posted floor plan, he is the semi-detached house partner of Pacc666. ;)
https://www.hausbau-forum.de/threads/welches-smarthome-system-fuer-unseren-neubau.43819/page-16#post-587373

That must be an extremely smart home-affine settlement.

- Glass switch? Yes, if you like it. I know they are popular but of course mainly because of the price.

I don't think they look that bad visually and the price is especially tempting at the beginning

Weather station, yes, available, also necessary; without one you usually don't even need to talk about any automation (eyes and ears).

Yes, a weather station was mandatory for us too, if only to control shading sensibly or to lower the shutters when windows are open at night/when away
probably much more is possible

Underfloor heating manual again? Ideally, it controls itself naturally without external interventions, especially not via a switch.

The underfloor heating is actually supposed to regulate itself automatically, I had just imagined being able to change the set temperature on the glass switch
Our new housing development is to be completely connected to local heating (we have no heating system in the basement)

What exactly does including mean? For lighting, most just mean on/off or at most dimming, and that 90% by button press, so you could also stick with conventional systems.

Are my expectations too low for KNX to be worth it for us?

I have imagined the following automations:
Automatic shading in summer
Automatic shutters e.g. at sunset or if a certain lux value falls below with anti-lockout protection for the terrace (only possible with window sensor)
Scenes like cinema mode, certain lights turn on and shutters go down x%
Light in the stairwell and hallway controllable without light switch (with presence detector)
but with all presence detectors I currently can't imagine it yet without experience

Our new housing estate is to be completely connected to district heating (we have no heating system in the basement)

You would have to look closely at how the system is ultimately set up. Even with district heating, there is relatively little to control in modern houses.

Are my demands too low for KNX to be worthwhile for us?

Contrary to popular belief... expensive, luxury, etc. KNX is always worthwhile, even in a 20 sqm one-room apartment.

Automatic shading in summer

Is generally strongly recommended with or without KNX.

Automatic roller shutters e.g. at sunset or when a certain lux value is undershot with lockout protection to the terrace (only possible with window sensor)

There is much more possible.

Being able to operate lighting in the stairwell and hallway without a light switch (with presence detector)

Then something to think about: Human Centric Light, e.g. for a visit to the toilet at night. Or the meanwhile widely accepted CCT lighting. Generally, different light colors at different times and for different activities.

but I currently can’t imagine everything with presence detectors without experience

Not everything has to. But the places where you spend most time and all the passage rooms.

You would have to take a close look at how the system is ultimately set up. Even with local heating, there is relatively little to regulate in modern houses.

Should the underfloor heating even be integrated into KNX then?
In our standard, we get an ERR for every room (which I believe is even mandatory for KFW55).

There is much more possible.

Can you give some more examples? I probably don’t yet know the true potential of KNX.

Not everything has to be. But where you spend the most time and all the passage rooms.

How can you set it so that the lights always turn on automatically as desired? That always depends on the situation and is often different and individual (I can’t imagine any logic that can cover that).

Should the underfloor heating even be integrated into KNX?
As standard, we get an ERR for each room (which I believe is even mandatory for KFW55)

ERRs aren’t necessarily a gain ;)
If possible and there's still time, one should even try to get exempted from them...

How can you set it so that the lights always turn on automatically as desired? That always depends on the situation and is often different and individual (I can’t imagine any logic that could cover that)

I personally always wonder about that too.
Apart from the fact that I couldn’t afford KNX in the house, the "automated lighting control" is the last thing I miss. At least in the house. In my case, no meaningful automation is possible because I want to decide myself depending on the situation and mood whether I need light or want to move around in the dark.
The same applies, for example, to the roller shutter control, which is "smartly" connected for me, but I still don’t set fixed times because we prefer to regulate completely independently and on demand. At least in terms of time; it’s different with shading and dependencies on outdoor temperatures, for example...