If you’re going to make a pad, an old piece of a mudflap will work great.Anything in that area is structurally solid. The OEM skid plate is super light. The raised knobs on the jack lift will be the biggest issue with the thin skid plate. A board will help if it stays in place on the jack.
I have a jack that came with a rubber pad. Maybe you can just order or make a pad to fit your jack.