Very much so same struggle. A few years ago I finally hit a point where I could self-soothe, but that was a forced learn as my co-regulator abruptly felt they couldn't be a part of my life anymore and I compleeeetely crashed (state of overwhelm was so prolonged and drastic that I had to admit myself to inpatient to not commit suicide. Not a fun time.)
But even now I feel like I'm just on an opposite not healthy train? In order to self-soothe and maintain such, I'm inaccessible to every other human being aside from work (cuz bills still have to be paid...that pressing matter makes brain function). I respond to no texts, I'm horrid to attempt to make plans with, etc.
I still cannot calm myself without calm people to assist, but have learned to push through it / force coping methods to ease symptoms a little until my brain decides to function enough to live. Or I dissociate until my body is forced to sleep. One of the two. I've lived that way for long enough now it doesn't feel too horrid...
Calm people feel like a heaven and I think I self sabotage because I know what happens now when I lean on that and then lose it. Aaaand similarly I tend to lose ability to self-regulate if I'm around someone negative/angry/stressed -- their mood will push me to overwhelm even if I was fine before.
TLDR I also have poor self-regulation skills. I've learned to sort of self-soothe but mostly have learned to just....deal? It's no fun, and I feel this hard.