Heli-coils
(goes under different names too) are a wire coil made from a diamond shaped, plus a thread tool 1mm. bigger in diameter than the defect one, plus and insert tool, plus the right diameter drill. These can be bought as a kit in one ore more sizes in a box.
First drill the hole, cut the new thread, place the coil in the insert tool and screw it in, Remove tool and take a punch, place it next to the tab on the coil that was used to screw the coil into position, use a hammer and give it a smal wack and the new thread is ready
There are other options, as in plug the holes and start again, for one, or your own suggestion comes to mind.
Best wishes
Per