Best retrofit smart home new build

ok

everything else, e.g. light switches, roller shutters.. should I do with Z-Wave (e.g. Fibaro) and everything that is not connected to the power, e.g. window contacts enOcean (e.g. Hoppe or Eltako)?

First of all, it is important to know what technical equipment you have... Ventilation? Air conditioning? Heating? There are thermostats that can receive EnOcean telegrams. These are used (especially) in hotels together with window contacts/handles for energy saving. However, this is not worthwhile with underfloor heating. Do you want to use the window contacts for security or for energy saving?

Always remember that in the end you have to somehow bring all these systems together so that it actually makes a difference! Therefore, definitely check beforehand with the preferred visualization or server what is supported!

When I read this again, I often wonder why anyone builds with property developers at all. You make (usually) the investment of your life and end up in often borderline levels of debt, only to accept what the kind developer happens to grant you. For that amount of money, I wouldn't want to accept such a take-it-or-leave-it attitude in any way.

the problem is we searched for a long time we could have decided between the house or none at all :)

We searched for land for a long time now we have a semi-detached house 150sqm + basement (heated) with 400sqm land
if we had found an affordable plot we could never have built with a basement for the price (the basement was very important to us)

Technical equipment: normal electrics, so light switches and switches for the roller shutters (electric roller shutters everywhere) underfloor heating everywhere (also in the basement) with individual room thermostats

Window contacts are mainly supposed to be for the roller shutter controls, so the shutter must not go down if the window or sliding door is open
I also want to be able to check in the app whether windows are open or closed or tilted

Technical equipment: normal electricity meaning light switches and switches for roller shutters (electric roller shutters everywhere) underfloor heating everywhere (also in the basement) with individual room thermostats

What does normal electricity mean? That’s a chimera.

A normal car is a VW Golf but also a Dacia Logan and also a 5 Series BMW. But the differences are obvious.

It doesn’t depend on what the developer slaps in there, but on how the wiring was done and which systems/manufacturers are used.

Electric roller shutters is a stretchable term and there are worlds of possibilities in terms of execution.

If, for example, Somfy (just an example) is used in your case, you might as well forget all Shellys and Fibaros and have to use the manufacturer’s own communication.

Window contacts are mainly supposed to be for the shutter controls, so the shutter must not go down if the window or tilt-and-slide door is open

Also here again, which manufacturers? How should contact X communicate with motor Y?

I also want to be able to check in the APP whether windows are open or closed or tilted

You are taking three steps before the first. Which app? Can the desired app even do that? Thinking about apps now is way too early and prevents you from first developing a concept at all.

If you are using, for example, Somfy (just an example), you might in some cases forget about all Shellys and Fibaros and have to use the manufacturer's proprietary communication.

I have read this in this forum quite often now. However, maybe as an addition, Somfy of course also offers "dumb" motors that can be controlled with any actuator.