Design of stair with upper segment open riser.

Removing requirement for overhanging treads should simplify fab in steel a lot.

This design is intended to be the simplest possible fabrication I could think of.
Cut 6x2 beam at 37.776 degrees for upper mount, weld to flange for bolting to versa-lam. (7.75" rise, 10" step)
May need a right-angle cut-out for lower part of stringer beams to mount to wooden landing. Weld angles or flanges to lower side to bolt to wood.
Build 9 deck supports. Not sure if they should be welded in place, or if entire stair frame should be built off-site then delivered and installed.
Pre-drill stair frame for wood screws to hold decks from below.
Weld rods mid-riser level to meet 4" opening code.
Rail posts welded to outside of stringer.
Lower rails shown, but could weld balisters directly to stringer.
Balcony railing inside hole, bolted to versa lam's.
Balcony ballisters can also be bolted from the side into the versalam.
from under stairs side
stringer mounted 2" from wall
banister posts welded to outside of stringer
Weld a frame for each deck between the stringers.

Trying to use a fairly small tube, 1" shown. Trying to retain open space between risers.

Pre-drill for wodscrews to mount decks.

Weld a small tube mid-way between risers to meet 4" max opening code