Costs for indoor railings / handrails in order - experiences?

It is only about the stairwell, which is still rectangular. Therefore, nothing changes about it. Nothing is bent.

Do the steps taper to a point or not?

Yes, the peaks are running together. But that doesn't change anything about the railing.

Hold a straight slat or something similar at the height of the handrail and take a look to see if/how the distance between the slat and the top edge of the steps changes, from step to step.

At first, I didn't want to believe the staircase builder that we need a curved handrail. After the demonstration, I accepted it; in our case, the staircase is probably even more curved than yours.

Do you think that the distance between the handrail and the stair tread varies? Yes, that is of course the case. Did you then use a handrail curved in height? Do you have a picture?

Exactly, we then took a curved handrail. The balusters of the railing are also curved accordingly. However, I don't have a picture of it.