Are you using the stair tool (21 &22)?
If so you can use Solid Element Operations to trim your wall (won't show in plan of course).
And if you select the 'Boundary' of the stair in plan or 3D you can adjust the shape of the stair - or just adjust the width of the stair flight in the settings maybe?
Barry.
One of the forum moderators.
Versions 6.5 to 27
i7-10700 @ 2.9Ghz, 32GB ram, GeForce RTX 2060 (6GB), Windows 10
Lenovo Thinkpad - i7-1270P 2.20 GHz, 32GB RAM, Nvidia T550, Windows 11