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Take your liners out and see if it’s easier to drill them out from the inside with a ~1/4” drill bit. Make sure to go pretty slow and make sure you don’t end up causing any melting if the rivets start spinning while drilling
I usually just drill them out and replace with a nice set of t-nuts. Also, heat up the end of a thin screwdriver with a lighter to make your holes in the strap itself instead of cutting, etc. If you cut holes they will rip as you pull hard on the strap, the hot screwdriver tip method ensure that the nylon doesn't rip.
Oh and just a tip, take the liners out first (seems funny to say but I see it happen all the time haha)