House construction planning: solid house or prefabricated house? With or without a basement?

Oh yes, regarding the elevator matter .... It is meant that we would at least like to plan the space for it today, but not install it immediately. The option should be cost-effectively prepared from the start.

Land plots are rather negligible in price for us.

The mentioned value does not include the land at all. The 2500 € per square meter refers to an ideal standard house with ideal standard equipment.

What exactly is that referring to? ^^

Square meter prices, which house construction naturally brings along. And especially this:

So because of KNX bus technology and 3 server cabinets: audio, video, network, private cloud (so absolutely no online clouds), video surveillance technology, everything should go through the technical room.
We want it absolutely clean. No cabinets in the room (only built-in furniture except for the bed and the nightstand, not a single cabinet should stand around in the room).
This means TVs and speakers should disappear in or on the walls and ceilings and not form dust monsters.

I do exactly this AV topic (multiroom AV, AV network technology, KNX/Crestron and co. in larger private and commercial projects) professionally and can estimate the costs quite well. Such a thing would at MOST work if you source all the mentioned things to HEK and do EVERYTHING yourself and leave out the Picea. Are you aware of what an installation extra effort invisible speakers alone mean in concrete or drywall construction? Apart from that, what acoustic measures are necessary in such clean rooms so that it doesn't sound completely tinny...

But it may be that you are fully into the topic as well. If so, have fun! It can be cool! But that’s absolutely not how you sound.

Your project, especially with these technical wishes (which I implemented almost the same way in my place), including the house, would head hard towards seven figures if you had to commission someone for it. I assume that the rest with this claim, especially regarding aesthetics, will hardly be Massa Haus with Ikea furnishing.

Regarding the elevator pre-installation, could surely say something. From what I see, he also once said something about "do it right away or don't do it at all."

Somehow my topic has also slipped here ^^ I think I started completely wrong. Actually, I thought I would first start with the questions regarding the headline. Basement or no basement? Brick on brick or prefabricated house? We have no idea at all. Are basements generally sensible and really cheaper in comparison to accommodate technology and storage rooms here? What is better, a brick on brick house or rather a prefabricated house with wooden frame construction? (As far as we know, the price is not really much different.)

The insights are already good, but you should first say goodbye to the whole rest.

I am reading here more amused than interested ...

So there are quite a few contradictions: your (undesired) luxury bathroom fittings are expensive, but certainly no comparison to a complete KNX Smart Home, elevator preparation, etc. etc.

Sure, you can research a lot on the internet, I did that too. But a real sense of space and how different square meter sizes of rooms feel—I lack the imagination for that. You really need model houses and inspiration for that.

Every person is strange in their own way, I’m certainly a bit strange in some categories when people get to know me.

But you can’t avoid making contact – which I would definitely recommend to you (although it might be questionable with the budget) to have a turnkey build by a general contractor, so you don’t have to take care of the craftsmen yourselves.

We’re building (because our house provider only builds shells anyway) with individual contracts, so we search for craftsmen ourselves and award the work, and you have to constantly “chase” them on the phone. Being shy around people is difficult there (and we are both rather introverted people who hate making calls ^^). We use a project management tool, and the recorded time so far is 3 weeks (counting 24 hours/7 days) just for planning. Without home office, it wouldn’t have been possible at all to make so many calls and appointments. The “saved” money through the shell house quickly disappears again in time and work.

But you’re nowhere near that yet anyway. Read through the forum here and shape your wishes and ideas. When it comes to the budget, many things will have to be cut anyway.