The gap between noticing overwhelm and being underneath it is very short, and that gap is the whole game. Once you're in it, no technique works especially well.
So the trick isn't the breath — it's the catching. Learning your own early signals is what makes everything after it possible: the reread sentence, the tab-switching, the sudden urge to do something else entirely.
Gratitude at that point isn't a mood. It's something concrete to hold while the alarm quiets down.
What's your tell? Most people have one and have never named it. Name yours and you'll start seeing it earlier.