I wish I had some magical advice on that but, good therapy (with skills and experience with adult ADHD and trauma), radical acceptance, medication, and developing positive coping skills is what I've got. Still easy to fall into negativity.

A good learning that I had from my therapist is that, regardless of level of success in coping that one attains, going through childhood and early adulthood without support for ADHD and/or other neurodivergence is psychologically traumatic. And that trauma needs to heal. Unfortunately, just like grief, the scars are permanent but, we can get better and let the parts of us that get overshadowed by the trauma and maladaptive coping strategies get some time in the limelight (easier said than done).