New construction - How to build economically sensibly?

New attempt:

So I have to say, my expectations for this forum have been 90% disappointed so far. Most answers resemble a wild chat. As I said, the remaining 10% are excluded. I probably share some of the blame myself, because I probably asked my question too imprecisely. But I have too little experience and possibly expected too much.

I just wanted to independently find out which energetic aspects (standards, building materials, construction methods) are not only useful for the general contractors but also for me. The budget question is certainly necessary in this context but should not trigger a fundamental discussion.

Ich lese zum einen von Polystyrol, zum anderen einen Preis, der 10% über Deinem "Limit" liegt. Das ist auch nur ein Angebot. Was später unter Deinem Werkvertrag steht, wird ein anderer Preis sein.

Thank you for your answer. We are planning with approximately 200k€, so +/-. Roller shutters, side door, so additional costs outside the construction service description currently amount to 15k€. For me, the 200k€ only referred to the basic equipment, not the extras.
It’s like buying a car. What is economical for me?
Gasoline, diesel, hybrid, or electric.
That’s what I want to find out. I’m happy to provide you with information about our planning that is necessary for the decision-making.

Just hire an architect, although it won't be feasible with 200k.

It's all nonsense anyway. One likes chocolate cake and the other enjoys strawberry tart.

One used to like strawberry tart, but the last one made him sick.

You can apply the same to house building.

You'll get 10,000 opinions here.

I just wanted to independently find out which energetic aspects (standards, building materials, construction methods) are not only useful for the general contractors but also for me.

The question is already absurd to me. The general contractor builds for you, not for themselves. In general, you can assume that general contractors build in a way that meets the minimum requirements (KFW). Anyone who wants more (KFW 55, Passive House) simply has to build better walls (walls as a representation of energetic equipment). And that is more expensive. It is rather rare that someone builds thicker walls than necessary in the standard equipment. So you can't really leave anything out there. Hence the reference to the budget. You can't leave anything out with your budget. It's like buying a car: all have 4 wheels and an engine. If you leave any of that out, you get a mess. And with your budget, you won't get a hybrid, let alone electric, and even a gasoline car is already tight.

All the energy measures known to me have some effect. Namely, energy savings. Whether they are financially worthwhile depends, among other things, on the future development of energy prices. However, these savings seem to be completely irrelevant to you, and you evaluate them solely based on whether they benefit your personal wallet and not the generations after you. With such extreme positions, an open debate is difficult because many here are more interested in finding a position of the controller that is meaningful for them.

The question is already absurd to me. The general contractor builds for you, not for themselves. Generally, you can assume that GCs build in such a way that the minimum requirements (KFW) are met. Anyone who wants more (KFW 55, passive house) has to build better walls (walls as a representation of energy features). And that is more expensive. It is rather rare that someone builds thicker walls than necessary in the standard equipment. So you can't omit anything there. Hence the reference to the budget. With your budget, you cannot omit anything.

It’s like buying a car: all have 4 wheels and an engine. If you leave something out, it will be broth. And with your budget, you can get neither hybrid, let alone electric, and even a petrol car is tight.

Diesel is supposed to be available cheaply

All the energetic measures I know bring something. Namely energy savings. Whether they pay off financially depends, among other things, on the future development of energy prices. However, these savings seem to be completely irrelevant to you and you evaluate them solely based on whether they benefit your personal wallet and not the generations after you. With such extreme positions, an open debate is difficult because many here are rather interested in finding a position on the regulator that makes sense to them.

That is not quite true, otherwise I would not have had a KFW 55 house with a heat pump offered to me. The question here is only how it looks in reality or whether it is like the "diesel scandal," where car manufacturers determine and state consumption and emission values that do not occur under real conditions.