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 need to know how to not express negative emotions at all whatsoever unless I’m alone. I know it can be done because it is done in many other people on the planet.
Helpful outlets don’t just fall in your lap, though. You have to do the work of trying things and see what sticks. You can start with small, achievable distractions if that makes it easier, too. For me, it’s taking a super hot shower and singing along loudly with music blaring. It’s just a short amount of time, but it stops my brain from going down a bad road sometimes when I can tell I’m about to have a rough time.
You are not a passenger in your own life, and you are going to have to start actively making changes if you want things to improve for you. It’s not going to just randomly happen to you.