Loud staircase noises from the neighbor's house - Is the staircase properly decoupled?

Our staircase therefore has space to the partition wall and is "only" fixed to the other walls, which works quite well if you want.

Maybe you should show this here, it is not equally easy to do everywhere, and probably not all developers are aware of it.

not my residential unit (is rented). However, I will check the pictures from the construction phase to see if we recorded that ... If so, I will gladly provide it later.

Enter sound insulation steel staircase into Google… that will make you a bit smarter. Whether there is also a solution, you have to check. I would then ask this question again in a/the green forum.