Tbh i think the dunk tank is stupid cuz its really just a stupid idea in total but there is no "dunk tank userbase". Users just do it cuz its a neat little activity on the site labelled as such.
I get the sense that you are doing your best to be a good influence and hope you continue to try to do so considering criticism people have as well.
Id add to the general speculation it seems not just depression but dissociation is your main issue. Life lacks salience because your brain is dissociating away so much pain the parts of your brain that are meant to feel things are overmodulated meaning no activity can be had.
I would look into bessel van der kolks work on traumas neurological effects!