Comparability of costs Architect vs. General Contractor

By the way, you can also buy the architect's design and then go to the general contractor (GU), who will then handle the execution planning, building application, etc. That would be a combination of both.

For me personally, an architect was never an option. Our budget is too low for me to have dared to do that. I was socialized too much in an automotive-heavy environment with development contracts, requirements specifications, and functional specifications.

So I gave the "forum design" from here to the GU, and his draftsman put it into his CAD program. A few walls and windows moved around, and it was done. Then it was just a matter of reading the building services description very carefully and negotiating my must-haves into the offer, such as underfloor heating design, larger tiles, or also venetian blinds.

After that, it means: staying reasonable and budget-oriented. It should be noted that reasonable GUs do not just roll the dice on their extra charges for special requests after signing. Usually, changes compared to the building services description are also requested from the craftsmen and offered to you by the GU + markup. The same will happen to you with the architect as well!

The architect adds something on top of the requested price from the craftsman? I don't think so.

With the good GUs, there is no surcharge to the offer from the craftsman, because the GU/GÜ has already included their profit in the total amount. At least that is how I know it.

In my case, it is partly like that, whereby it comes to the same thing if the craftsman only states the catalog list prices as a surcharge each time and does not allow to negotiate, because he was previously negotiated down so hard by the general contractor for the standard that he no longer has any margin and tries to make everything back in the surcharges.

I believe this is comparing apples and oranges. Most of the advantages of architects cannot be quantified.
Since, as already mentioned, there are good and bad ones everywhere, let's assume a good architect: enthusiasm, status gain, customer service, freedom, flexibility, and more creative options.
This also involves disadvantages: longer construction time, dependency, and many clients cannot handle freedom and flexibility. And because of these factors, a house with an architect is often 20% more expensive than the estimate.

What we really don’t like are sometimes inexplicable extra costs in the offers from the GÜ/GU and especially the helplessness / lack of ideas when it comes to questions about the placement/planning of the house on the property. It feels more like a car dealership where they sell you a car – they also don’t care where you drive it.

Yes, you are just one customer among many if it’s a bigger general contractor (GU). They want to sell the cookie-cutter house to the client; it’s not a custom house, and that’s why the time factor for the customer is also tighter. (Compare tailor//boutique//department store)
But even in a department store, you can get good advice and buy good quality.
You just have to “cooperate” a bit more. Many end consumers nowadays save on services: in my opinion, architect builds and GU builds are not much different in this regard. Only that with one you have to (GU), with the other you can (A)... but with the latter you want to, with the former not really.
Inexplicable extra costs are relative: if you consider that with a walk-in shower not only the shower tray is omitted, but the tiler, screed layer, and plumber have more work… an additional wall is tiled, below that a waterproofing barrier, then an extra charge of €1000 becomes understandable. Most GUs have elaborate modular systems...

Then for me it was just a matter of reading the construction specification very closely

I know many houses from the 80s/90s that were built with an architect. Back then, there was no full-service GU yet (which actually offers many advantages)
And there’s really nothing special about those houses. Simple, practical, good. You can’t necessarily tell the architect across the street or residential area because even with an architect, most people only build what they can afford and what’s mainstream.
But occasionally, you can find beautiful and less beautiful exotic examples. When I get to enter such a house, I enjoy the individual interior layout, which is not necessarily more practical than standard but more about the spatial experience.

For me personally, an architect would never have been an option. Our budget is too low for me to have dared to take that step.

Same here with us.

If you don’t have to do pirouettes on the plot and can more or less find yourself in the construction specifications, you can build cheaper with a GU in good conscience for yourself and your budget.
But if, for whatever reason, you don’t cope with the offered options, plan extras on every wall and corner, get upset that somewhere in the utility rooms a pipeline or downpipe is visible and not concealed, that the beam between kitchen and living room is not hidden in the ceiling but visible, dream of built-in extras that are not provided for with the GU, then please go with an architect. But that will also have to be paid for.
For example, we were able to realize a great open space with our GU and the type house. If we had built with an architect, he might have added an indentation, recess, or whatever somewhere. Maybe the staircase would be somewhere else, but then the house would also be 30 cm wider on the architect’s recommendation – but that would certainly come with a five-figure surcharge and a much longer planning time. With the GU, it’s now just as it was offered. And we are happy.
From experience, architect-built houses are more expensive because you have to pay for the service.

We decided back then on a general contractor who not only has standard houses but was also willing to fulfill wishes. In hindsight, we were glad. There was a fixed price, many things were done cost-neutrally (walls moved), and if there were any additional charges, they were passed on 1:1 or directly settled with the tradesman of the respective trades.

It is difficult to find the right general contractor who deals fairly with additional costs and flexibility. From the feeling alone, it is the medium-sized companies with few houses per year.