ᐅ Single-family house, single-story, knee wall, upper floor windows

Hello, good evening!

I would like to thank all active members and moderators here once again, as I have already received some good advice just by quietly reading along. However, we are currently struggling with questions that cannot, at least for me, be clarified on the internet.

Here is the situation:
Planning a single-family house with very tight specifications
Maximum house footprint: 121m² (1300 ft²)
One story
Lower Saxony

We would like to have a dormer on one side and narrow windows in the knee wall on the other side, if possible. Unfortunately, we have encountered conflicting information from architects, so I would like to ask the following questions:

Which parameters are taken into account when calculating the upper floor, in order to make the best possible use of the knee wall height?
The Lower Saxony building code states that a full floor requires a clear height of at least 2.20m (7.2 ft) over two-thirds of the floor area.
I also know that the external thickness of the gable wall is not included in the calculation.
Are there other factors that should be considered to maximize the upper floor area, such as stair openings, interior walls, or similar?
From what knee wall height or under which conditions are narrow windows on the roof slope side allowed on the upper floor, or are they impossible in a single-story building?

If you need any additional information about our project, please let me know!

Sorry for my non-expert terminology!

Good luck
Tom