First of all diagnosis isn’t a solution path.
It is not just one thing. I see a mixture of beliefs that are creating the different emotions and behaviors you are describing. There are beliefs that prop up a sense of superiority, and beliefs about poor self image at the same time. Add in assumptions of how others perceive you, self judgment, and the seduction of power and control that go with anger. (which by the way would only be appealing if there were a sense of powerlessness to begin with)
It all adds up to a belief system in the mind running out of control.
Take a look at this
breakdown of beliefs behind the issue of anger to get an idea of how many things work together to build an emotion.
Of course recognizing and diagnosing the issue isn’t worth anything. It’s like having a cactus needle under your skin and someone pointing out what cactus you got it from.
For the concrete steps you asked for check out the audio series in
Self Mastery on my website. The first couple free sessions are small steps but will give you a place to start. The exercises in the paid sessions will begin to create more impact as you progress.
Or consider doing some sessions with me personally.
It is absolutely something you can change. But by my experience it isn't something that changes by some kind of fluff affirmations or "mental" steps as you found out.