I use a keyring ring on my coat zipper as its easier to pull and basically never going to break, This means a wider hole for it to pass through, which I made. I also made it flatter (hole was enlarged in the direction of the zipper teeth)

For my coat I used 110% scale in the width and the rest at 100% (cura 3.6)
Did about 10s of filing of the small triangle that joins the two main parts of the zipper (as the top of my zip is wider) and bam it slides on from the top.

Oh and I used the scraper from my printer to press the top zipper tooth into it, It needs to be flattened slightly to fit and pressing with the scraper from the side of the zipper is flawless

If you use cura, scale it before you rotate, Cura really doesnt like you doing both and if you dont scale before rotate, scaling in Z might scale in Y etc

EDIT: Uploaded a .prt and .step, whilst I did upload the SW CAD file for others to edit, I remembered not everyone has Solidworks

Creality

CR-10S

No

No

0.2

100%

No sizes changed apart from Hole at the front

File with a file small enough to fit where the zipper teeth would IF NEEDED.
your goal is to file the bottom of the small triangle that joins the two bodies