Chronic DPDR is usually suppression you don't know you're doing
Had chronic DPDR for 7 years. Five months ago I started accepting parts of myself I had been suppressing without realizing it. Since then the DPDR has been slowly dissolving. I feel alive again. I inhabit space and time again. After 7 years behind the glass.
I think now chronic DPDR is very often caused by hidden suppression. Not always classic trauma in the obvious sense... often it's parts of yourself you've hidden away as "not me," without knowing you did it. A truth about yourself that wasn't allowed to exist in your environment, Sexuality, identity, whatever. Then the system dims everything to keep that one part out of view. And you pay with 100% of your presence.
Dig. Look at what you won't let yourself be. Accept it, even when it's inconvenient. It worked for me. It's not a guarantee and the timeline is different for everyone but ig it's a direction that could work for more people than the standard "grounding techniques"
Peace.