New build - which SmartHome system?

KNX is quite easy to understand. How to get the ETS has already been described by mycraft. What I find missing in your list are all the sensors. You need them for smart functions and for the logic. Don’t let yourself be unsettled by the fingerprint. It is (with the right scanners and setup) more secure than RFID and most standard lock cylinders. If you want everything in one system and visualization, easily expandable, etc., I would choose KNX. You are then not tied to one or a few manufacturers. Planning and sufficient cabling are the most important things. Or you can combine various systems like Lumpi. That also works. Possibly several bridges or apps are necessary. No central programming... But it works.

I don't have any personal experience yet, but according to the electrician (whom we know well and who is also knowledgeable about KNX), free@Home is intuitive for the end user to operate.
We didn't want KNX because we also didn't want to spend ages learning it initially and then need ages again to make changes a year later because we no longer remember how it works.

is free@Home intuitive for the end user.

Unfortunately, that’s where the advantages end.

We didn’t want KNX because we also didn’t feel like spending ages learning it, and then if you want to change something a year later, it takes ages again because you don’t remember how it works

KNX administration is more or less intuitive once you understand the terminology, because it was specifically designed so that an average electrician with no IT knowledge at all can manage it. In other words, anyone who can operate a smartwatch or even create an Excel spreadsheet with formulas is hopelessly overqualified.

KNX is an excellent, future-proof, and manufacturer-independent standard. What is really "simple" - I just came from my parents, my father, a former engineer and suffering from Alzheimer’s, constantly messes with something and at least once a week an electrician is hired to get, alternatively, the conservatory control, heating, outdoor lighting... working again. If you want to grow old in that house - better not. Turning the light on and off with a simple switch is not something you forget. Even push dimmers eventually become a challenge,

Well, you don't have to, for small changes the ETS demo is enough and it's free. Later after commissioning you can use it to change the little things that don't fit.

Oh really? I've never tried it intentionally but I did once forget to plug in the dongle (=demo) and then ETS didn't even want to import a project, if I remember correctly.
You can open, edit, and update devices in projects with more than 5 devices using the demo?!

Yes, that's correct, they naturally don't want to import anything. You have to come up with workarounds. It's not obvious at first glance how, but it's possible. It's about the fact that you can already do quite a lot with the free version or the Lite version if you want to spend little to no money.

With large and complex systems, of course, it's a lot more work and sometimes not functional after all, but in a typical single-family house, everything is quite straightforward. It's like always, those who save in the wrong place end up losing out.