Yelling makes people hear your volume, not your point.

Once the volume goes up, it becomes the subject. The person in front of you is now managing being shouted at, which takes all of their attention, and whatever argument you had disappears behind the fact of the shouting. You can be entirely right and still lose the conversation this way, every time.

When you feel it rising, say you need a minute and take one. Come back and lead with the quietest version of your point. If the thing matters enough to yell about, it matters enough to actually be heard.