I might buy this house and have never lived there.
The porch has an big air space of maybe 4 feet underneath the slab. Some of the rebar at the bottom edge of the slab is visible when peering in. The rebar is not the small round stuff; it's more like the T-shape metal 'fence post' thicker design.
Of course, the crack also needs repair. There are other smaller, less visible cracks.
The hole has been there for a long time so the concrete around the hole feels a tad crumbly.
The porch is perhaps 6 x 20 feet. I didn't measure the slab thickness, but it's probably 4-6 inches. There is a basement block wall towards the back side underneath.
If it is not a good idea to use a strong concrete patch, why not?
Otherwise, if it is not a good idea to open up the hole a little and fill the huge air space with something, perhaps a concrete slurry, why not?
How about using a Trex or wood product (or some stamped design) to re-cover the porch after patch since it would otherwise look ugly?