We built our house with KNX this year. While our electrician did all the wiring, I did the programming myself. It has a steep learning curve, but if you're in IT, you'll probably get the hang of it pretty quickly. The system is very robust and offers a lot of flexibility. Almost all our componenents are from MDT (https://www.mdt.de/EN_Start.html). They build really great products and are quite affordable. Compared with components from other manufacturers we use (Theben, Weinzierl, Steinel) I think their applications and manuals are also far superior.

I have since connected the system to my home assistant installation, and enjoy the added flexiblity.