“Is there another way to fix the leak in the 6 inch PVC pipe?”
Yes, but you won’t like it either (however, you will dislike it less than going through the slab).
You or the repair person will need to tunnel in under the slab to repair the leaking pipe joint. The easy part is tunneling in. The hard part comes when the repair is done and you have to pack fill and try to re-compact the now disturbed and expanded fill which was removed. Then, after re-compacting the fill as it is placed, you will need to termite treat this area either by injecting in from the side or by drilling holes through the brick from the top (just what you were trying to avoid doing, damaging the brick). There is a catch with the brick, if the mortar joints are wide enough, you can go through from the top in the grout joints and then just patch them when done.