Bungalow floor plan, approx. 120 m²

That could work.

The property is not subject to any development plan, so one is quite free in the design.

That must mean little. The inclusion requirement of a section 34 area also restricts; a local statute may have rules on building lines and the like. : how was it again with you? - there was some guideline affecting the positioning of the parking spaces ...

Links are not allowed. Just google the state building regulations of Saxony-Anhalt... the regulations apply. Without a development plan, you are not lawless.

Attached are a few suggestions and approaches for simply Life. One draft, however, is 17 meters long and 8 meters wide.., intended for N-S orientation. The plot also seems to call for that. And since you write that there is nothing going on on the street anyway... I haven't measured anything else. They are sketches. Relatively open, each with a "discretion corner"... Here you go Ps. On the east side you have to keep 3 meters clear to the neighboring property, with streets I know it is 5 meters that must be kept clear. I hope you can see from the crossed-out walls where this is heading

Anbei ein paar Anregungen

... which remind me a lot of old times. In the 80s, I was a fan of this style of floor plans, which on the German market only Hosby had.

I actually quite like the third "suggestion," the child can calmly go to the toilet at night and the parents are separated from the child. Utility room not next to the children's room but still close to the kitchen (in case some supplies should be stored there).