Arguing to win and arguing to understand sound the same for about a minute. Then it gets obvious.

Early on, both look like engagement, with questions and attention and reasons. The difference shows up in what happens to new information: somebody trying to understand changes shape when they hear something good, while somebody trying to win goes looking for the next angle. You can hear it in whether questions get answered or converted into traps. Nobody hides which one they are doing for very long.

Check yourself mid-argument by asking what the other person has said that you accepted. If the answer is nothing, you are winning rather than listening. Say one thing they got right, out loud, and notice whether that is hard.