Steelman before you argue: say their point better than they did. Then they’ll actually hear yours.

Most people have never heard their own argument put fairly, which is partly why they keep repeating it louder. Stating their case well, including the part that is genuinely right, settles them, and a settled person can listen. It also stops you winning against a version nobody actually holds. If you cannot make their case, you do not understand the disagreement yet.

Write their best reason in one sentence as though you believed it. Say that to them first and check whether you got it right. Then give your own point once, and notice how little pushing it needs.