I study cognitive neuroscience. Meditation is extremely evidence-based. It is literally one of the most evidence-based things there is in terms of actions you can take to improve mood, executive function, focus, general cognition, etc., it's almost as backed as physical exercise. Of course, there is also a lot of woo-woo spiritual stuff around it, but you can just ignore that side and use it effectively. Not sure about breathwork, I'm moderately skeptical of many the claims made about it, but I haven't looked super far into it comparatively.