Financing a detached house of 140m2 in Bavaria - Is it possible?

I did not intend to express with my contribution that everything is better in Greece. You completely misinterpreted that. Every country has advantages and disadvantages, and you can't just pick the best parts everywhere and then compare countries.

11ant recognized this quite well. You could apply for a complete construction and then build step by step. But after 3 years the building application expires in Germany. Therefore, you would actually have to apply for each "children's room" individually, which makes modular construction unattractive.

For example, we applied for a building permit for our subsequently erected terrace roof. The whole thing with the option to enclose the roof later with glass sliding doors. Since it was not executed within 3 years, this option has officially expired. Why? I have already received questioning looks because, with the building application, I had to ask a neighbor with a sheep pasture if he had any objections to the terrace roof standing 15 meters away.

It was a serious suggestion to inquire in the direction of serial construction and modular construction. Shall we outsource the political discussion?

Simply back to the original question. This should not become a political discussion.

It was a sincere suggestion to inquire in the direction of serial construction and modular construction methods.

However, there are too few providers for a single-family house (I do not know a single provider). Modular construction/serial construction makes sense where uniformity is accepted and a corresponding quantity is possible (about 10 houses).

could a shell construction perhaps still be a possible alternative.

The better basis in such cases is clearly a shell / shell construction.

I don’t see it that way.
Whoever calls themselves Fachfremd and writes..

I am aware that in addition to the shell construction many other costs will come up (finishing, electricity, heating, plumbing, exterior facilities, etc.), I have already started a cost calculation here

Maybe a few additional info:
There is supposed to be a lot of own work done by parents, friends, and acquaintances. But the "professional work" has to be done by companies.

.. I do not see them capable of making a shell construction ready to move into.

What kind of own work did you have in mind?

I don’t see it that way. Anyone who calls themselves non-expert and writes like that... I don’t see them being able to get a shell house ready to move into.

No, we see it the same way, see:

If your forum name is at least somewhat fitting, I advise against finishing a shell house on your own.

The better basis in such cases is clearly a shell / shell house.

It was after all not referring to the fact that the OP should choose this path. Rather, if at all, it was about that in the case of the discouraged project, it’s better to choose a basis of “shell plus” than “move-in ready minus” when cobbling the house together as a “semi-finished product” from rudiments and individual trades. I stick to this – and here I don’t see us in contradiction – the OP as a first-time builder should not seek adventure but rather have his architect plan the house with a tender, and in this tender put in his own bid for the trades I, O, U, and Y, while for the lots of trades A, E, U, and all consonants only the professionals should bid. So A to H (earthworks, foundation/slab, and complete shell) to a shell general contractor, and afterwards he himself where he can and may, in combination with the professionals. For the trades where he can and may, he should prepare offers that must meet the same standard as those from contractors. Then he applies a truly comparable benchmark to his own work and will be surprised not always to be cheaper (even if he realistically calculates with half* the hourly wage of his profession). *) Rule of thumb for the hourly wage for own work: tariff wage of the main profession (not base wage, only overtime surcharge, usually 25%) times 2 (because due to lack of experience and rapidly declining fitness, on average half as fast as a journeyman) effectively results in half the hourly wage – everything else is self-deluding unfounded hope.