After having received a lot of help so far, I can finally share my experiences as well.
A year ago, we faced the same decision about how and especially with whom to build. We visited many developers for solid construction as well as various prefabricated houses. I think the style of the house is a matter of personal taste.
We decided on solid construction and finally chose a developer directly in the town who also has the claim to plan individually instead of duplicating model houses.
We no longer want to miss the advantage of regional proximity. We believe that in every construction project there are many questions, problems, and decisions that can be much better resolved personally and straightforwardly and on the way to work on site instead of by phone or email or only in person every two months.
Moreover, smaller regional providers also have a reputation to lose, which possibly increases the motivation of the developer.
Nevertheless, you have to take care of the construction progress every day and will have to have discussions over and over again.
In hindsight, we would only take fewer services from the contract in order to be able to award individual trades ourselves and to avoid the upscaling trap.
Good luck