Ultralight,
I would say you are already well on your way, as you white-knuckle along. You are adopting a minimalist style; you are relatively self-disciplined in the grocery store. You are coming to grips with your compulsive behavior seeking "junk food" … and you are asking for ideas. Kudos!
Support first!
Now a couple of ideas...
Have you read the memoir by Bullitt-Jonas, Holy Hunger: A Woman's Journey from Food Addiction to Spiritual Fulfillment? The author's father was an alcoholic, and around age 10 she developed compulsive eating. Her memoir details her personal journey in the Overeaters Anonymous 12-step program. She is an Episcopal priest and a Harvard PhD. Her faith perspective may seem simplistic to an atheist, but it does appear that OA worked for her.
OA is structured around meetings and sponsorship, but their website contains some on-line resources. https://oa.org 12 Traditions, 12 Steps, Recovery that is physical, emotional, and spiritual.
As rosaruga suggested above, there may be healthy alternatives to the junk food you are concerned about. (Minimizing harm as a goal, rather than the goal of abstinence.) I would add my own personal favorite, Medjool dates (watch out for pits!), and copious amounts of filtered water with a twist of lemon or lime. Also, there is quite a satisfactory crunch in crisp celery, an apple or a carrot. On occasion I will air-pop hull-less popcorn.
Be well!