First, don’t tell me that the answer is just to “not bottle things up”, because that’s objectively incorrect too. Society doesn’t want you to have any negative emotions.

I’m guessing you’re a man. Society imposes this upon men in particular.

Tell society to fuck off. Have emotions, experience emotions, and process them like a human being.

Then take it a step further, and learn how to handle them like an emotionally intelligent human being.

I need to know how to not express negative emotions at all whatsoever unless I’m alone.

This is part of the problem. This is not what you need to know. You need to know how to express negative emotions without losing control of yourself or your reaction to your emotions.

I know it can be done because it is done in many other people on the planet.

People bottling things up and exploding when in a safe space is part of the problem.

I’ll echo the idea of anger management, or even therapy in general.

Nobody who is healthy hides away their emotions. You’re not alone in feeling the way you do. Society is sending you signals that you need to do something unhealthy, but that won’t actually fix the problem.