I think an attic doesn’t have to be used. It offers advantages for a low cost.
To stay with Rensch-Haus, they have pretty bungalows. Take the Madeira, for example. A bit too classic on the outside. There are more modern ones available, though. However, I saw it as a show house. The parents' area is a dream. The entrance looks wow, like a villa. That stuck with me. Ok, the living area is a bit small. You can enlarge it. Then you get a staircase between the storage room and guest/office/child room, and the WC also moves to the side, and you get a nice small cloakroom. No shoes, no bags, no bottleneck in the entrance. The floor area is a bit smaller. It also feels stupid when a 160 sqm basement is unused, there is space in the bathroom for another bathtub and shower, the 2 children's rooms. Unfortunately, I can’t find the floor plan anymore. I think it was Luxhaus, they had the extremely spacious living area arranged in such a way that later, for example, a bedroom can be set up. 80 sqm is quite a statement for 2 people.