A complex profile as Laszlo suggested will be the easiest solution I think.
You can SEO a stair but the floor plan (2D) view will not be affected by the SEO so you will have to redraw the plan view anyway.
You could create a "stair from selection" to get the angled side you want and then mirror a copy but you will still have to hide the join with a white line in plan but not so easy to hide that join in 3D.
I just tried this quickly in 17 but could not turn the handrail off in 3D either.
But I never use this method so I may well be missing something.
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