ᐅ Stair railing with an 18 cm gap from the wall

Hello,
we have a straight staircase that is bordered on one side by a fixed-glass window and on the other side opens to the room. The height to be covered is 2.60 meters (8.5 feet).
The open side will be fitted with stepped glass panels. However, on the other side, there is a gap of 18 cm (7 inches) between the window and the wall/staircase.
Should we consider adding a second handrail, or is the gap too large?
Alternatively, are there affordable temporary railings or bars that can be installed and later removed (for when the children are older)?

In public buildings and offices, this spacing would not be allowed for safety reasons. I would also avoid planning it this way in a private setting, primarily for my own safety.

How should one imagine this? 🙄 Are there any pictures or plans?

How did this come about? Who planned it that way?

Here is the floor plan of the positioned staircase and an example photo.

With children, I would DEFINITELY install a railing for a staircase like this. And you do realize that these stairs are very, very noisy unless you sneak around like a cat and weigh as little as a fairy?
(a good example of "beautiful but unfortunately very impractical")