Thank you very much for your answers. Since I was traveling for work, my response is only now coming. The prices in Munich are very high. We are budgeting 1.5 to 2 million euros for the house. I am very aware that my requirements will be reflected in the costs. The development plan has been worked through and we are allowed to build 325 sqm of living space; according to the development plan, a flat roof is also possible. Can you recommend an architect or general contractor? A prefabricated house is also an option for us, as we have heard many horror stories about solid houses. It is a fact that a prefabricated house is manufactured in a production facility, thereby reducing the error rate. Since we currently have a shortage of skilled workers, we like the idea of everything coming from a single source, so that there are no misunderstandings regarding warranty. According to Weberhaus and Keitel-Haus, ceilings 3.50 m high in the ground floor as well as windows or glass surfaces that do not conform to standard dimensions are feasible.
Based on your previous description, the only prefabricated house provider that comes to mind is Huf Haus. This provider is experienced with "houses with lots of glass" and seems to work reliably and seriously. Unfortunately, our budget did not allow for HUF HAUS, but it might be a good fit for you.