It sounds like you've had a real journey with your anger @Lax, I'm so glad that you've been able to share this here. That learning that anger signals some sort of boundary crossing is so interesting and it sounds like this really helped to shift your approach to managing this emotion, from trying to suppress it, to understanding it.
I definitely find anger to be a difficult emotion myself and feel that I'm personally working to understand it more and accept it as a useful and valid emotion, as it is communicating something to us, like a boundary being crossed.
P.S. I wanted to extend a warm welcome to the forums, so good to have you as part of the community