Shelly Pro Series vs. Homematic IP wired vs. bus wiring experience

The question may/should be asked and answered by everyone themselves.
Roller shutters, garage door, and outdoor lighting -> later asked about connection with the weather station and tilt function (I assume window contacts?)

so it is already moving in the direction of automation, where one should ask oneself this question. The answer is also up to each individual.

For me – since I have also significantly dealt with KNX:
In a new building, where my automation goes beyond one discipline (e.g. more than just simple blind control), I would opt for KNX.
In an existing property, however, the threshold is quite different, as the initial effort becomes completely different.

In a new building, where my automation goes beyond one discipline (e.g. more than just blind control), I would opt for KNX.

I agree.

In an existing building, however, the threshold is quite different, as the initial effort becomes something else entirely.

Correct. And then I add: For small gimmicks like lights/blinds or similar, KNX is like using a sledgehammer to crack a nut.

It's also a question of the learning curve. With the mentioned "ready-made modules" you just do click-click and have an automation that is satisfactory. With KNX you have to first parametrize and then also learn some programming. Sure, you can plan much more, more stable and future-proof with it. If you know how. But most people don't. It's like analyses in companies: Sure, you can do great analyses and evaluations directly on the database with SQL and Python. But the average manager wants to do click-click in a graphical environment and can only do that. If you're lucky, they know a bit of Excel and don't add up the fields with a calculator to then enter the sums in the total field (really seen that).

& - I agree as well. Especially the comparison with flashy, colorful interfaces is really good and important - especially for run-of-the-mill gimmicks. Ideally, there should be a realistic assessment of one's own abilities and the desired level of automation beforehand.

I believe that KNX is overkill for my simple requirements and the costs are acceptable at around €1000 in addition to the conventional installation for this level of automation.

the costs are, at this level of automation, about €1000 additional to the

It seems that the additional costs have not been calculated correctly. Direct wiring of each individual consumer to the distributor would most likely cost more than this amount. It certainly depends on the number of consumers to be controlled, but if it is a single-family house/semi-detached house, it would be much more than that. I think you have to calculate the number and type of consumers and then determine the additional costs per consumer and compare them with different systems.