Prepare new building for future wireless "smarthome"

So he can install the regular electrical system and I then replace the switches afterwards?

There are several ways. You can change the switch or install an additional part behind the switch. Both are pretty much the same price-wise. So if you are happy with the look of your switch program, then a small part has to be placed behind it. The bigger the box, the more relaxed you are afterwards. You can google the difference. "Kaiser Tiefe Dose" and Kaiser Elektronikdose".

What is important to me:
Shutter controls with window sensors
Heating with window sensors
Lights
a few sockets
and a video doorbell

Everything is no problem except maybe the video doorbell. I would inform myself beforehand and probably even install it directly. Theoretically there are battery/rechargeable battery solutions, but if possible I would avoid that. Therefore, the right cable must be there.

Why battery replacement? If the light switch or shutter switch has power, then they don’t need batteries, but of course the batteries in the window sensors need to be replaced

Yes, I mean the window sensors. The others work without - provided the switch is really in the right place.

What are the electronics boxes?

See above.

So have deep flush-mounted boxes installed everywhere

What do I need for the video doorbell?

The doorbell should definitely be connected by cable and not have a battery

Deep sockets should always be installed anyway. Regardless of whether automation is desired or not. It is simply better for the electrician later on and faster and easier in the event of any changes.

What you need for the video doorbell depends on the system itself. But I would provide LAN and telecommunications cables, e.g. (A-2Y(L)2Y 4x2x0.8).