Our floor plan for discussion

Architect or general contractor, that is exactly the question we are facing. In our euphoria, we already started planning. It would almost be a miracle if an architect couldn't do it better. I’ll probably leave it for now.

Regarding the development: In the immediate vicinity, up to 3 full floors can be found, mostly gabled roofs, partly half-hipped roofs. That would be the "local typical" development. In terms of size and type of structural use (and that's what §34 is about), we would be within limits. However, we are not planning a flat roof, but a low hipped roof. When it comes to roof types, the district offices and municipality have nothing to say – even if they like to believe and try otherwise. For those who don’t believe me, I recommend reading the relevant public law commentaries :)

There is nothing against painting it yourself - it's just time-consuming and the learning curve is very flat (and you need a high frustration tolerance - with the first 30 drafts you will be advised to throw them in the trash). One should keep in mind that professionals can still do it better afterwards - and I don't mean catalog floor plan representatives... they often do it even worse because, besides your requirements, they are also tied to their own forms, etc.

for the first 30 drafts you will be advised to use the trash bin).

The first 30 drafts do not belong in public at all - my opinion.
A draft grows - for a layperson, growing takes multiple times longer than for an expert. And if correcting a corner still takes that long - whoever finds it too long should go to the expert... :)