How do you fight this battle?
i believe Addiction is a state of mind; if you are a gambling addict; there is only one way to win this battle; just one way. And that way is to determine in your heart to stop gambling and quit. After making the decision; you then write the gambling sites, close your accounts, delete their apps and move on with your life by getting yourself engaged. Whenever you feel like gambling, send the funds to your fixed account and move on with your life.
Simplifying this in terms of self-will, your determination to stop and quit away is very important, you can do those things that you mentioned but if you are fully or deeply addicted the help of your love ones who can help you to seek for professional help is also needed, it's not that easy as it is, especially if your addiction is really deep.
But, the most important part as I mentioned it is your self determination and will to stop your gambling participation.
It's only the beginning of the long road to take and a different venue to help yourself to stay away from gambling.