This is a clip for a relatively small strap roughly 28 mm or a little more than an inch. I copied the clip from my running belt strap and modified it to be a bit sturdier when 3d printing.

It's used to manage the excess strap to avoid dangling. I've used it for my backpack and it works for me. You could also use this if you have a running belt.

How this works is you bend the arm sideways to clip the strap closest to the bag and use the other side of the clip to secure the loose end. You might have to pray some pieces that will stick together after printing.

I might be making a longer version to manage straps that are wider, in the future.