I find pursed lips breathing extremely powerful and effective
Do it whilst breathing only through the nose. Purse your lips with a challenging expression (see for example https/google.de/search?client=ope... ) This is an acupressure thing. Pressing on the point between the nose and the upper lips promotes taking a deep breath. See video on https/youtube.com/watch?v=PiSq-Wn...
All the best. Richard Friedel