Prepare the smart home for future expansion (no wireless/cloud)

So with the constant vein fixation, I give up.

Are there no usual implementations?

Yes, of course. It is common to create a room book in which the personal requirements are recorded. Where and what kind of light, how controlled with which functions? Where and how many blinds with which (central) functions? Where and how many outlets with which functions and consumers? Where is what kind of visualization needed? From where should what be manually switchable? Which automations are desired and which data are needed from where for this? Once the requirements are fixed, then you plan how to implement these requirements as simply/cost-effectively/future-proof as possible. For example, "light" ranges from 230V on-off via dimmable internal/external, "intelligent" luminaires or LED strips up to complex DALI solutions that are to be integrated via gateway. Only when all this is clear can you start to deal with where which cable is needed and where the other end should be.

This is not a task for a weekend, even if you are already familiar with it.

Are there example wirings somewhere, e.g. from experience reports?

Of course, there are certain basics. So
- all roller shutters/blinds go directly to the control cabinet
- all lights go to the control cabinet
- everywhere a sensor, button, or flush-mounted device is to be installed, a green cable goes there – but this is laid in an open ring from socket to socket
- switchable/measurable outlets need at least their own phase in the control cabinet or their own cable

But that only helps you to a limited extent. Because if you think about this, you are already 90% done. But you are still at the very beginning. And your time is no longer sufficient for that.

It all reads as if every home installation reinvents the wheel because it is so incredibly complex.

No, it is not, but reading three pages is not enough either – not even for a standard installation.

My ideas:
Bathroom/toilet lighting and music
Roller shutter control throughout the house (weather, time of day, heat/cold protection)
Sun (weather) sensor facing south somewhere coming out of the wall?
Remote control of front door and garage door
Automated heating/cooling depending on the weather
(Smoke detector was advised against, costs high)
We have one blind, raise it in strong wind.
Reduce the number of buttons in the living/dining room or assign different functions (scenes?)
Outdoor and living room light control dimming/time. If light is on outside = no access to terrace shutter. If terrace shutter is down = light off.

- Each roller shutter 5-core cable into the control cabinet to a blind actuator
- If door and window contacts then
a) via local push-button interface (with green cable) or
b) via binary input in the control cabinet
- Weather stations are mostly via green cable (but at least should be considered, working with line coupler)
- Motion detectors with green cable
- I see lighting as a sensitive topic:
a) DALI gateway and control each light via 5-core cable (in my opinion only sensible for dimming and I have the feeling that DALI is losing importance)
b) KNX with flush-mounted actuators in the ceiling (then 3 cores + green cable) – also only really useful for dimming and colors
c) KNX with control cabinet actuators (relays or dimmers) with corresponding cables – great for on/off, from an electrical engineering point of view I am not in favor of dimming this way
d) Gateway for Matter, Hue, etc. possibly switched via control cabinet actuator (relay) with 3-core cable
- I would probably represent music via WLAN depending on demand – probably not sufficient for audiophiles (there are plenty of options online)
- Timers for fixed times are usually integrated in the IP interface/router (+ here you can easily access it externally via RasPi or server) or via 'KNX small server'
- I find the solution from Gira for smoke detectors not bad but also not perfect (one with KNX interface – green cable – and connect all others among each other)
- Temperature sensors are often integrated in push-buttons (e.g., MDT GT2, etc.)
- Heating hopefully mostly does not have to be regulated in underfloor heating with heat pump due to self-regulation effect; if necessary there are heating actuators (I would integrate directly with green cable in the heating circuit distributor)
- 'Outdoor and living room light control...' is only programmed in the logic engine (regardless of 'KNX small server' or external server)

AND AGAIN, this is half-knowledge I have collected out of interest (so I give no guarantee for correctness, efficiency, etc. – and I gladly welcome input from people with real professional expertise ;) ) and it is much too brief to implement it properly in house construction.

The problem here, however, is that it has little to do with a typical standard installation. That simply does not bring everything into the control cabinet.
Hybrid solutions usually do not combine the best of both worlds but rather the problems of both worlds.

I just want to know recommendations from someone. Roller shutter 2 wires to the light switch, from there 5 cores into the distribution board. Light + music from the ceiling 4 cores into the distribution board. Are there any example wirings somewhere, e.g. from experience reports?

should slowly realize that with this basis or when asking such questions, not even a standard installation without KNX will work without expert help. In this case, I would consider simply having the installation done in the standard way by the existing electrician and at least install deep electronic boxes at the switch points. Then you can still retrofit some kind of radio or WLAN system later if you want to automate something occasionally. Trying to go for KNX or other bus systems in the available time simply won’t work. You can still put Home Assistant on top of that, which, for example, supports Shellys very well. Just read up on what integrations there are and then select the desired devices accordingly. There is also something available for door communication.

Yep. Either you do it the classic way or go straight for Smart Home. But then completely, and that usually involves changing the electrician - for example, my electrician clearly said: We don't do Smart Home. I think that's good.

As a middle ground, I actually only see putting in deeper boxes and generally laying network cables in the right areas. It definitely won't be a proper Smart Home, but you can then automate one thing or another, for example via Zigbee.

Are there no usual implementations?

One of the biggest advantages of KNX is that tailor-made solutions can be created from standard components. If you try to steer it into "usual" paths, you end up with the well-known unnecessarily expensive click-clack installations with KNX components.

Slowly dimming the light according to the time, for example, what is needed for that?

On the bus side: power supply, dim actuator, time (e.g. from the IP router), logic module (e.g. Raspberry with XY), green cable. If you also want to control/trigger/stop it manually, touch sensor or push-button interface.
On the house side: power cable and light bulb.

I think it’s good.

I think it’s bad in today’s times. But that’s just my opinion.