I know this might not help that much but I try to keep myself from getting to the point of no return. If I feel myself getting close to it I say "I need to step away from this situation/conversation so that I can calm down"

Yes. My worst self harm scar was because it was out of anger. I don't really have much advice besides taking some mindful deep breaths and trying to calm down.

Knowing what can trigger your depression can help

my dad struggles with this -- finding a safe outlet for the anger is crucial. If possible, therapy could really help. I used to have very similar experiences myself and it started to take over my life. But for me personally I had to force myself to not burst in a destructive way, but try and find the source of the anger. For me, fear, insecurity and guilt was the source. So I had to really talk to myself or someone I trust and figure it out. Hearing advice from other folks would really backfire so anyone who's willing to listen and acknowledge what you are feeling might be helpful.

Yes, it's a good thing I work from home. Once a day, frustration drives me to extremes and I lose my mind. I make sure the camera is off on my monitor and my phone is on mute. Then I holler and scream and call everybody the worst things that I can think of. It's ok because they can't hear me, at least, I don't think they can hear me. If they hear me, they think I'm a maniac for sure. I try to do better, but my work seems to come up with new and exciting ways to torture me on a daily basis. Good Luck!

Taking a bathroom break to just go and do some breathing exercises and identifying that your depression has been triggered. Identifying why you're mad is a major step!

You don't suppress it. That's the trick. I have the same issue so I started kickboxing and muay Thai. Its helping me manage and so far so good.