Ming from Agents of Speech explains how to handle tantrums: reduce talking and questions, observe what your child actually wants, then teach them easier ways to ask for it like gestures or sounds instead of screaming. During a meltdown, stay emotionally neutral and watch closely, then gradually give them what they want while pushing them to communicate more.
We don't actually tell you to ignore. We tell it to reduce the level of language input, reduce the amount of questions asked, reduce the amount of tension you give them so that you can free yourself out to observe. When you observe that he wants something, this is when you can teach them to use some gestures, use some sounds and words to get what he wants. Because saying words or using gestures is actually easier than throwing a tantrum. If you teach them that, it will be much easier and you might say, dude, this might be too hard for me. And I don't know how to do that. When they're throwing a tantrum, I can't think. And that's cool. Ignore them for a bit. If they come to you, don't let them hug you. Keep it as neutral as you can so that I can observe what he wants. And after that, give them what they want. Like once, you know, give them what they want little by little, and then increase the demand for them until they talk.
