I think dp is tricky to understand and treat because it's more of a symptom and can be triggered by different things such as, panic attacks, anxiety, depression, trauma, drug use, head injury, physical problems,etc. Its trigger is not one and treatment will certainly not work for all. Mine is chemically induced this together with depression. Treatment for trauma-induced dp doesn't work for me at all not much anxiety either.
and also regarding my depression, i don't have interest to begin with so what distraction technique are you talking about? That one day when I suddenly got extreme interest, dp just vanished. I didn't use it as distraction technique (I don't think it'll help much if you use it that way). It just happened and I felt so much in control. Doing a boring task didn't make me snap back to dp mode, because when i feel in control, I can SEE through the bullshit the dp is telling me, just like a normal person would think of it.
I picture dp like a naughty kid who follows you everywhere you go. You engage in sth, he talks but it doesn't matter what he says cuz you're busy. But then when you do a boring task,you lose interest and instead listen to him again. If you are in control and know yourself really well, this won't happen. You will dismiss his nonsense very quickly and he will turn to be your enemy. So again, feeling in control is very important and also trying to change from third person perspective to first person's.