This house is all engineered joists so they can’t cut through them. The new waste pipe will drop into a box soffit in the laundry below and connect to the plumbing tower space where all the other pipes run.
Not hard to do and the cost isn’t crazy. Remove jacuzzi tub, remove toilet from closet, put new commode in area where tub was, redo floor and add privacy half-wall where the commode will be. Add box soffit to accommodate the new waste line. $8k