Those aren’t carabiners, they are small quick links and it’s very unlikely anyone is going to be randomly carrying those in the backcountry.

The simplest solution to a broken backpack buckle is another buckle. If you’re going to carry something, carry those. They’re light and cheap and should be part of the repair kit for backcountry travel.

You can also simply thread the strap through the webbing loop and tie it off. Hard to get the length exactly right but works in a pinch.