So how did Pink specifically break volleyball with her powers? Was it like an accidental power shockwave but still by her own tantrum issues or did she actually punch her or something else?

The damage to Volley was accidental, but the pattern of behavior was something she consciously chose to repeat. You ever, like, live in daily fear of someone whose anger is really destructive? Maybe they haven’t attacked you in a long time - maybe they haven’t even directed their rage at you directly yet - but they yell and break enough stuff in your vicinity on a regular basis. Eventually, that perpetual state of alarm your body and mind are in, wondering when they’re eventually gonna come for you or hurt someone else, can take a psychosomatic toll.