Floor plan of a single-family house, slight slope location, northwest orientation

laut Bebauungsplan

What does it say exactly?

Baufenster ist auch fix vorgegeben

Where is the building envelope?

weil hinter dem Feld auf der rechten Seite in ca. 500m eine Bundesstraße verläuft

That kind of information definitely belongs in the opening post: why things are as they are.

das Grundstück ist im unteren Bereich leider etwas schmal

That is not a negative feature when you consider that you have just under 19 meters, slightly below the standard value of 20 meters in width, but consistently along the entire length, and a good plan.

laut Bebauungsplan sind 1,5-geschossige Häuser zulässig eher offen

fits fine

konservativ oder moderne Bauweise modern (?)

probably fits as well

Was gefällt besonders? Warum? Der offene Wohn- und Essbereich. Der offene Blick auf die Felder Die Gaube im OG

I would place the dormer to the southwest

offene Küche, Kochinsel offene Küche geplant, Kochinsel gewünscht aber aufgrund von Platzmangel verworfen

It is not open. Yes, it is not closed with a door. But it is a tight G shape, also squeezed into a corner, which separates it. The line of sight from the front door leads to two tall cabinets instead of an axis into the garden area. How old are you?

Maximum Heights/Limitations
According to the development plan, the house must be built exactly on this alignment.

Built on the alignment probably means the front building obligation after 5 m?

Builders' Requirements
Style, roof shape, building type
Country house style, gable roof (gable side facing the street), single-family house

Is gable side facing the street mandatory or just a wish?

Garage, Carport
planned, questionable whether the garage should rather be positioned on the right to avoid blocking the south side

Would it be allowed to place the garage on the right side boundary as well?

The appropriate excerpt from the development plan or the textual information on where to find it online is missing.

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Regarding the spatial critique, I can only agree ... the sizes of the areas should allow a kitchen island and everything else to be sensibly accommodated.
But, the children's room and bedroom are somehow botched.
Also, neither for the bed in the children's room nor for the storage room has the 2m line been considered.

The stair drawing does not align cleanly at the exit.

Living room - 5 m to the TV wall is quite a lot.

And sightlines, already mentioned them, often do not catch my attention, but here especially the stair with an extensive end on the ground floor is planned, but simply runs into the closed storage room wall.

I also do not find the flat roof projections for the ground floor extension and covered entrance very successful.

I consider a mirror image of the ground floor not so easily possible, unless the garage can really be moved to the right ... however, this mirroring does not fix all, in my opinion, flawed points.

Sorry that it all sounds so crushing.

What does he say?

open construction method; floor area ratio = 0.4; plot ratio = 0.4; ridge direction parallel to the street (mandatory); gable roof; height of the vertical exterior walls on the eaves side must not exceed 0.8m, measured from the top edge of the threshold; max roof pitch 48 degrees; dormers max. 2/3 of the building length

Where is the building window?

identifiable by the neighboring buildings, construction may only start 5m from the street, all houses are aligned in one row. 3m setback from the boundary

How old are you?

We are in our early 30s. How is that relevant?

Built in alignment, does that mean front building obligation after 5 m?

Exactly, all houses on the street are aligned like this

Is it mandatory for the eaves side to face the street or just a request?

Unfortunately mandatory

Would it be allowed to place the garage on the right side directly on the boundary?

that would be allowed

visible by the neighboring buildings, construction is only allowed from 5m away from the street, all houses are aligned.
3m boundary distance

And how deep is the building envelope? Asking about it is a bit tedious.

We are in our early 30s. How is that relevant?

.. therefore I actually noted everything relevant in the questionnaire that is supposed to be answered.
Age is important because of the basic needs and perspectives, which are different for a 30-year-old than for a 60-year-old.
The basic needs are usually not recognized by the builder themselves, perspectives are mostly over- or underestimated.

And how deep is the building envelope? Asking is somewhat tedious,. .. that’s why I have actually noted everything relevant to be answered in the questionnaire. Age is important because of basic needs and perspectives, which are different for a 30-year-old than for a 60-year-old. The basic needs are usually not recognized by the builder himself, perspectives are mostly over- or underestimated.

We also briefly addressed age in the questionnaire. Thanks for the clarification. The depth is, in my opinion, not specified; at least as a layperson, I cannot find a relevant paragraph. The only noticeable thing is that all houses are aligned in a row and extend more or less deeply. Only the maximum buildable area is defined, but it is so large that we do not exceed it.

the other, that the draft is rubbish.

I am not saying that the draft itself is rubbish. Rather, it is its creation that is rubbish (from which nothing coherent or substantial can arise). The sun rises in the east, and that remains so even if you mirror the floor plan. Consequently, rooms are either correctly positioned before or after the mirroring. If you want to mirror so that room L comes to the right (where it is considered more correct), it does not automatically mean that the room R, which then comes to the left, remains appropriately placed (because that would require that location does not matter for this room). Apparently, the planner here has cobbled together a performance phase 3 without having properly completed the basis in performance phase 2. Then it was work on not architect fee level but on vending machine gum level. Detention, six!
Such planning belongs to be crumpled up rather than mirrored. And if necessary, redone as many times as it takes until the planner has learned that you do not submit children's drawings for adult money.

Honestly, one is somewhat hesitant to start a new planning on a whim, which will once again cost a mid four-figure sum without knowing whether it will really be better under the given conditions.

New planning, yes of course. But not by chance, rather developed properly with craftsmanship. Demand improvement or refund from the planner via complaint. And then have module A (= performance phase 1 and 2) completed first before "building on" it—starting in third gear doesn’t work. The conditions are not to blame.

The 34 cm walls caught my eye.

That’s why I was thinking in the direction of a "prefab" house enthusiast—although the original poster has so far not explained where the unusual dimension otherwise comes from: 24 cm brick plus 10 cm insulation?—the planner must have thought of something.

We also don’t like the upper floor, hence the request for input in this forum and not the direct step toward a developer.

At first, there was talk of a tender, now I read "developer" (and suspect layman’s jargon for "general contractor"). So, is the tender meant not to refer to such but to be a price inquiry with only turnkey GCs as participants?; and is an Excel oracle meant to determine the winner of the casting? (then I wish good luck with making the apples and pears building service descriptions share the same name). At least don’t forget to ask question 2 to all candidates (to offer a tried counterproposal from their "catalog")!