That you pay for the marketing-etcetera overhead applies to
all Big Names regardless of construction method. / kitchen aspect: my recommendation would be "Der Kreis" / Varia, which is an association of independent kitchen specialists.
I do not see that with KfW40 automatically
all solid builders are eliminated; that only seems to apply on the condition that one limits their search to the Big Names. Has the OP already "bothered" to crawl through the local "Experience with construction company XYZ" section to see what is reported about builders near the surrounding district towns?
What the Big Names
really do better are two things that do not benefit the builder or are even to their disadvantage: namely first optimizing their money-making process and second limiting complaint losses. Although I consider the claim that "in new development areas 80% is built regionally" slightly exaggerated, it is otherwise a key reason for the idea of the "property service": the brand heads are annoyed by the market share of owner-managed companies.
/ aspect of eliminating trades "construction stage turnkey minus" - without wanting to call myself an insider, I think I can explain this simply: all supra-regional general contractors (including the timber frame panelers among them) want to minimize their logistics and cost calculation problems, where the difficulty lies is where (possibly for the first time) cooperation with a small subcontractor is required. Floor layers are - even in Frankfurt Darmstadt Offenbach, but especially in Kleinkrotzenburg - typically small businesses. With them, they have more risks than added value in these trades, so away with them. Picking cherries in reverse.
These are not regional, they just have their headquarters or something with you.
Regional companies are those in the area you learn about from the yellow pages because their websites are hardly found since the experts build and do not busy themselves with optimal advertising presences. Or because you keep your eyes open when you travel to the countryside.
Apparently, you only stop at those you know from advertising. Immoscout, prefabricated house providers, Das Haus, Schöner Wohnen – they do not report on builders who build 50 houses a year in Buxtehude or Bielefeld.
That's how it is. And
only that. The vocational schools for bricklayers or carpenters are the same for the Big Names and the owner-managed. None went to Harvard (or Hogwarts – because none of them can do magic either).
Incidentally, I consider
one thing absolutely certain: on the topic of heat pumps & co, I see the OP in the greatest danger of all partial aspects to be badly taken advantage of if he does not thoroughly fight ignorance there:
there lie the biggest bombs for the "wrong" technology, inflated prices, disappointing paybacks, and so on. Compared to that, every interior wall paneling or other construction service description detail at the fifth decimal place is trivial. Whoever knows too little but says: "Waiter, bring me the best champagne" (KfW40), will be fooled and picked like a Christmas goose.