Which smart home system is suitable for our new building?

I meant more in terms of functionality

Can you create better/more complex automations with free@home than with a wireless smart home?

Can you implement meaningful automatic shading with free@home?

Take a look at Loxone, you can program and implement almost everything according to your own wishes.

Loxone is not offered to the electrician; he only offers Free@Home.

How complex can the automations be with Free@Home?

Would you recommend Free@Home or rather a wireless smart home? (e.g. Matter) that can be retrofitted later by yourself

Just a silly question. Your electrician is already doing the wired version of F@H?

Yes, of course the bus version of F@H

He is convinced by F@H because it can be built modularly
And later with F@H you can retrofit everything you still need
Often also by yourself

And later with F@H you can retrofit everything else you still need Often even yourself

That's exactly where the problem lies: you can retrofit everything that F@H offers, no more. I can't say anything about radio systems, I've never tried any. But if your electrician is laying bus cables anyway, then he should rather install KNX sensors and actuators right away – it would be no different from a craftsmanship point of view. Buy ETS Home and configure it yourself, and you are maximally flexible – and you have the assurance that all parts of the house can communicate with each other (I don't know if that works so easily with radio). As I said: read Heinle's book, it gave me a good first impression.