Most arguments are two people defending different points while thinking it’s the same one.

Each side builds an increasingly solid case for a claim the other was never disputing, which is why the frustration climbs while nothing moves. You can go twenty minutes like that, both correct, both convinced the other is being unreasonable. The trouble is not disagreement, it is misalignment, since there was never a shared question. Noticing that is much faster than winning.

When it feels like talking into a wall, stop and say what you think they are arguing, then let them correct you. Ask them to do the same back. Half the time the argument dissolves on the spot.