Which sensors for what? Inspiration

Can you briefly explain what you are doing with the switch TR? And where are your 5 switches housed and what function do they serve? I would be really happy if you could address that.

In the technical room, I have a waterproof switch for the ceiling light and a socket underneath. Heating, part of the ventilation, etc. are housed there. I also did it the same way in the electrical engineering room. It’s also cheaper than BM. As mentioned, it doesn’t help you how we have something. On one level, the house consists of three sides of glass. You can't put a switch there anyway (except sticking on a wireless switch). Sections, rooms, size, usage are different.

Well, whether it benefits me, I will see. You could also categorize it as a "strong interest in the topic and resulting curiosity." But no hard feelings. I can understand that it is "annoying."

Is not annoying. But you have to find out for yourself what you need. In the garden house, there is also the combination of waterproof switch + socket. Another switch in the pavilion for the floor heating... Most of it is solved via logic. It can be remotely controlled anyway via panels or mobile devices.

So far, a server was not planned.
However, I have seen that MDT offers a fairly affordable logic unit.
Does anyone know it, is it any good?

And again about the push buttons.
In which rooms do smart push buttons make sense from your point of view or where are 2-/4-/-push buttons sufficient.
Guest WC, utility room, technical room, and corridors don’t need any at all in my understanding, right?

If you plan without a KNX server, you also plan without an "app," meaning no control via tablet/smartphone.
Besides lighting, you probably have blinds in rooms like the technical room, utility room, WV, which would then need a switch. Unless you only want to control them based on time/brightness.
With a simple server and app, you would at least have the option to have a "digital switch" for everything; they don't have to be visible on the home screen. In case the blind in the technical room should be raised at night, for example.
With the app (visualization/server), I can do without many switches; without it, the dependence on logic/time controls would be a bit too high for me personally.

I can recommend the X1. We initially also did not plan any visualization. My playful nature, however, quickly demanded it. I didn't really want to get along with EDOMI; it was too complicated for me to learn. After a brief test of the Jung Smart Visu, it was replaced by the Gira X1. For a simple visualization on the phone, this is enough for us, and thanks to the integrated logic engine, a lot can already be done. Because the X1 also serves as an IP interface for programming, it is a real price tip. Sonos can also be integrated for some time now, but I connected that via IP-Symcon. At that time, this was not yet possible via the X1. Timers are also possible with it. KNX without visualization – or rather logic engine – is possible but leaves a lot of resources unused. The nice thing is that something like this can be retrofitted quite easily with KNX. Unless you want some fancy tablets on the wall, you don't have to provide much except space in the control cabinet for visualization. We consciously decided against the tablets from the beginning, and I wouldn't know what I would need them for.