ᐅ Poorly executed plastering work in new construction – any experiences?

Hello everyone!
In my opinion, the plastering on our stairwell, as well as on some of our interior and exterior walls, is very poorly done (see pictures).
However, our construction company denies this.
Could you please give your assessment based on the pictures?
How would you handle this situation with the construction company?

Hard to see on the phone. It just looks blotchy – was it painted?

I know it is difficult to see.
Yes, the painter from the construction company was here and repainted. He left the house saying there is nothing more he can do if the plastering is done so poorly.

It looks "wavy" in the pictures. Are these masonry walls or timber studs covered with drywall?

What level of quality was agreed upon?

I would say: It’s not attractive, but it’s not a defect either. No chance of getting that approved. Grazing light is also not allowed for defect assessment. At least two pictures are taken with grazing light.