Different parapet heights in one room

Have your architect provide you with a rendering.

This was already shown at the location mentioned in post #5.

By the way, at that spot I would not only pay attention to the two windows but to all the windows. In many houses, the windows are thrown together like a dog's breakfast.

In the present case, it is indeed a lively mix, but authentically following the circumstances and, in my view, completely okay. However, there is - in my perception disproportionately among ladies born in 1986 - sometimes an almost pathological latent dissatisfaction with the balancing of facade views.

Does it look silly with different parapet heights

but on adjacent walls.

No, it probably wouldn’t look silly. Not outside and not inside either. They are two different types of windows, and also in different construction areas (knee wall and gable side). Don’t worry!

"What looks good?"

Doing "everything the same" is one method, emphasizing "lively differences" another.
Both are completely okay (in my opinion).

This is — as so often — a matter of taste.

If one hasn't dealt with it much yet, it can of course be helpful to get to know other people’s opinions.
But it always remains one's own decision.

Personally, I often find "differences" more pleasing than "sameness," but I also love symmetry (which is a form of sameness). Sometimes my preference might just be a rebellion against restrictive norms... and I also find that justified.

What I want to say: training one's own judgment and the awareness that every decision can also be seen differently, I consider sensible and useful.

What I believe I can say for sure: There is no objective beauty, or rather "rightness."

Thank you very much for the help! We will leave it as it is, I think it is hardly noticeable inside and from the outside it fits better too. To be honest, I often find it difficult to imagine the rooms just based on a plan. But I think it works like this :) Thank you very much and have a nice Sunday!