To barter with Piglins, normally you have to drop a gold ingot on the ground and they will rush to pick it up. For some reason, not only are they not moving towards the gold ingots, but they won't pick them up and inspect them.
UPDATE: So, I had mob griefing turned off in the world where my screenshots are provided. For some reason, the bartering system is tied to that. I feel this may be an error, in which you cannot barter with piglins if you turn off mob griefing.
You can always just right-click them while holding an ingot