In my experience of working with anger in therapy, I'm not completely sure how I've done it and I know there's no real endpoint because it's ongoing.

If you have trauma in your background, anger is a natural component of that (perhaps tracing back to the original fight or flight response). It's normal to feel angry at someone who has abused you.

I also work in a field where my clients (I'm not a T) have been terribly traumatized by (usually) families, sometimes (strangers or acquaintances), and almost always (social service systems, including religious, mental health and healthcare more broadly, services like public aid, and legal systems. Hearing their stories pisses me off a lot, and public interest work even in the absence of direct client work is also very aggravating, as some to many professionals screw things up or deliberately try to block clients from assistance that they need.

I also found that I was angry in the middle of grieving some recent losses, and sometimes the people in my life irritate or annoy or anger me. So anger is kind of a big thing for me and, like you, the idea is to express it and work with it so you don't lash out at people and so it doesn't run your life. But I think anger is just very, very normal, and there's no magic to resolving it.

What I've gradually found is that learning healthier ways to express and deal with it made me a much happier person. Denying it or should-ing myself that I must not be angry was a real failure. Lashing out at people or being unkind or condescending or otherwise negative towards someone is what I try to minimize, so just becoming aware that I feel anger (for a long time I think I didn't). Knowing what the anger is about is only part of the issue for me, although sometimes when exploring why I'm angry I can see it's connection to something in the past where I think that this person is tripping my anger wire because s/he reminds me of a person or an event from long ago. Being able to examine my thinking about the present thing pissing me off sometimes helps me move beyond it, because I can see how it's different than the past. Most people are not trying to hurt me even though I'm angry at something said or done, and trying to unpack that has been helpful to me.