Do you know what fibre the zip tape is? If it’s synthetic you can arrest the fraying with heat (lighter, iron, or temp controlled soldering iron and Teflon paper) before attaching new tape. Use a heat-cut blade to cut new tape to graft on, so you get a low profile overlap/join with no fraying, then crimp on a new pin (or the old one you carefully pried off).
You potentially can get inside the garment, and cut the required amount of zip tape from the top of the zipper - there’s sometimes a good few cm of tape beyond the last tooth - but it’s a big ask and risks the upper tape fraying if it’s not finished properly.
.....with something like this, I guess you don’t have anything to loose before reverting to a full replacement if it doesn’t work.
Do you know what fibre the zip tape is? If it’s synthetic you can arrest the fraying with heat (lighter, iron, or temp controlled soldering iron and Teflon paper) before attaching new tape. Use a heat-cut blade to cut new tape to graft on, so you get a low profile overlap/join with no fraying, then crimp on a new pin (or the old one you carefully pried off).
You potentially can get inside the garment, and cut the required amount of zip tape from the top of the zipper - there’s sometimes a good few cm of tape beyond the last tooth - but it’s a big ask and risks the upper tape fraying if it’s not finished properly.
.....with something like this, I guess you don’t have anything to loose before reverting to a full replacement if it doesn’t work.