Which smart home system to choose - special requests present....

Don’t I need tons of gateways/hubs etc. because each system initially comes with its own to connect?

Correct. Although much already works relatively well out of the box with the respective radio standards. The approach is just rubbish, but advertising still suggests that everything can be done so easily by yourself. As I said, with the Alexas and Googles of this world it works fairly well, but you pay for that with the presence of Alexas and Googles.

If you are somewhat IT-savvy, then really take a look at Home Assistant, OpenHab, or ioBroker as recommended earlier. I have evaluated Edomi (purely KNX), ioBroker, and Home Assistant for myself and built small demos with them, and ended up with Home Assistant. There are ready-made integrations for many things (to connect your various systems), and if not, NodeRed already comes out-of-the-box.

I'm just a bit worried about brokers and co that it might turn into a time-consuming hobby instead of a smartly operating home working quietly in the background....

So I use iobroker and a huge number of shellys. You really have to engage with it. Here is an example of how I visualized it in our hallway. The whole thing runs in the visualization with the mediola system. The actual logics are all on the iobroker.



The whole thing is actually only intended as an information center. Roller shutter control, lighting, etc. All runs autonomously in the background.

why iobroker and mediola? why isn't one enough?