Offer comparison and liquidity planning for new construction, any experiences?

Of course, it also depends on your expensive plot and – I’d bet everything on this – your demands. If I build a house for a good €3,500/sqm, then I build very high quality (= expensive).

I don’t think it’s the demands:
Walk-in showers, floor-to-ceiling windows in the living room, sliding door to the terrace, oak staircase, and electric shutters. But turnkey.
We don’t need smart home and no further options so far. They are purely the standards from the B&Ls.

However, we only inquired with the well-rated companies: e.g. Weberhaus, Schwörerhaus, Haas and Bien-Zenker

How do you calculate?
Why not use €400k equity, look for a cheaper house provider and not repay at all costs (10 years KfW = can repay in 8 years if you can afford it – but your liquidity does not look like that).

Private loan for 20 years: €625
KfW for 30 years: €730 (+/- depending on the repayment-free years)
€360k residual loan: €1,500
Total €2,850 monthly.

==> You can easily reduce that to a €2,500 rate with another house (a bit smaller, fewer demands)

The child benefit is already included in the income. Even with your calculation of a €2,850 monthly mortgage + €2,700 expenses + additional costs €300 (electricity, water, etc.) we are again at the available income. It then presupposes that everything runs perfectly, nothing gets more expensive, and nothing unforeseen ever happens.

Which cheaper providers could you recommend? What is especially important for us is the overall service and the processing. We can only take care of very little ourselves timewise and also don’t want countless defects. Having to deal with legal disputes afterward (which unfortunately is often reported).

And how much savings could one expect?

Which cheaper providers could you recommend? What is especially important for us is the entire service and handling. We can only take care of little ourselves in terms of time and also do not want countless defects. With legal disputes afterwards (which one unfortunately reads about too often).

Comparable quality costs a comparable price. Cheap providers are something like Town & Country, Danwood, etc.

I would either buy a perfectly suitable house off the shelf (which, given the house size, drastically shrinks the providers – it’s no longer really an off-the-shelf house) or go into the race with an architect (whether it then runs through a general contractor or in individual trades can be decided later).
200 sqm is really quite large.

That is what the architect is for, whom you pay for all the tasks and supervision during construction. And legal disputes / defect problems occur with all variants. Even the most expensive provider won’t help if something is really botched.

And how much saving could one expect there?

With the same quality and equipment? None at all. You can’t want a Mercedes but place an order for a Dacia. But the Dacia also drives and gets you from A to B.

I would also have liked to build the suitable off-the-shelf house, but the development plan is extremely restrictive and only angled houses with a shed roof are possible. The houses are so long and narrow that even when omitting the angle, unfortunately no standard house fits. We do not need the same quality and equipment. As mentioned, service and the "all-round carefree package" would be more important.

I would have also liked to build the suitable off-the-shelf house, but the development plan is extremely restrictive and only angled houses with shed roofs are possible. The houses are so long and narrow that even omitting the angle, unfortunately no standard house fits.

We don't need the same quality and features. As mentioned, service and an "all-around carefree package" would be more important

Then I would be interested to know how you obtained the offers. What exactly did you do?

Initially, I inquired with a text including the floor area, number of rooms, and the building documents from the authority. However, the providers ideally wanted floor plans (at first, I thought they would create these directly with us). We then roughly drew the floor plans and specified the following special requests:
Turnkey
The staircase in oak
Floor-to-ceiling windows only in the living and dining area
All shutters electric
For the floors: calculate a material price of 50€/sqm
Sliding door to the terrace
Walk-in showers (ideally tiled in the upper floor)
To make it comparable, everyone should also offer the services that we could theoretically commission separately:
Foundation slab
Carport
Green roof
Photovoltaics + storage (10kWp + 5kWh)

By now, we would also omit the oak staircase and the additional costs for the floors. Likewise, we could do without the carport.
Green roofs and photovoltaics are required - however, photovoltaics could be dimensioned smaller.

The floor plans are complete rough drafts and are only meant to show which rooms we would like to have. We would definitely review them with an architect. It was simply important to clarify beforehand what we can actually afford.

Additionally:

For obtaining quotes, we spoke with the representatives on site and developed it live.