Outdoor rug maybe? Try something with a flat weave.

It's possible to have the stone ground smooth, but it won't be inexpensive. Be prepared to have them do the whole thing though; you'll probably want it all done when you see the area under the table.

What Kevin said. My SIL bought a Brown Jordan set to use on her dock - with frequent guests. The leg style of the chair catching on the dock boards was pointing to a tip over, likely a fall by someone. She credited it to a mistake made and replaced them....and I was the happy recipient of the first purchase ;)

Change the profile of the tip of the legs. Round it over or add a chamfer to prevent the leg from catching to corners of the stones.

I feel ya. I’ll never buy heavy chairs again.

Thank you for answering We have ordered an outdoor rug & outdoor pad BUT don't know yet! What did you do?