Very first floor plan draft of the ground floor

Basically yes, but do you really know the work of everyone just because you know them? Village gossip is always a thing as well. It doesn't matter to me whether I sat in the same school bench with them or how many beers we drank together. More important is, for example, if the architect says he tries to charge dearly for every little deviation or if he lets things slide. How punctual appointments are kept, etc.

It’s not the first heating system we get from him and not the first roof...

For my grandfather, this will be the new residential building in which he is directly involved, and as a neighbor, he will spend half the day on the construction site anyway... I am quite aware that I cannot correctly assess everything myself.

5,000+ for the plan I could definitely accept, but 30,000€ is definitely too much.

5,000+ for the plan I could definitely accept

The architect earns his fee only from a tiny fraction of what the client sees in the form of drawings. And even what you pay for individual service phases is negotiable.

Deriving views and sections from your self-designed and here collectively deburred floor plan and transferring everything into CAD on a stick so that the architect can base the approval planning on it, that’s also done by a draftsman; and the hammer for the piggy bank doesn’t have to be that heavy for that yet.

From the approval planning onwards, the architect becomes much more indispensable; and: even if grandpa always carries his army revolver on the construction site, I firmly believe in the usefulness of an architect during construction management. Usefulness also in the sense of "worth their money."

Incidentally – but not intended as an incitement to take advantage – I regularly hear of architects who prefer to do their studied job below HOAI rates rather than flipping burgers. The other extreme – billing as much as possible and working lazily – may exist, but it is not the rule. Rarer than voluntarily correct craftsmen, I would say.

You can't tell me that an architect is financially worthwhile. Where is he supposed to get the 30k from? You might have significantly less effort and overlook one or the other small detail, but overall I just can't imagine it.

You can't tell me that an architect pays off financially. Where is he supposed to get the 30k from?

I think 30k is too high for a single-family house. It would have to be on a polygonal plot with one side on rock and the other on swamp

I just asked someone today -> 28k. All other examples on the net also fall within this range

Just go to a HOAI calculator, it shows you exactly what each service phase costs. With >30k you are almost already at service phases 1-8.