It doesn't annoy me if the windows are not ruler aligned, so I wouldn't mind a different sill height; I find it relaxing.
But why are all the windows so small? Is it the side facing the street and you deliberately want to give little information? Then you can use more stylish windows. Narrower ones that can be taller, that is, not the normal parapet height, but taller ones that give light from above but are not visible from outside. So-called light strips. But then they would have to be planned longer.
If privacy is not an issue, I would make the windows bigger overall.
But generally I find such a facade more relaxed than windows which are always symmetrical and strictly arranged one below the other. But that's a matter of taste.
It would be interesting to see what the other facades look like. It has to fit together somehow. If the other three facades look more like an urban villa, then the facade doesn't match the rest of the house. If the other facades also have a loose design, it fits.